PROFIBUS Technology and Application

02092 PNO Titel AR1 07.08.2002 11:14 Uhr Seite 1

System Description

Open Solutions for the World of Automation Theproductionofthisbrochurewaskindlysupported bythefollowingPROFIBUSCompetenceCenters

Weprovidecompetentand dedicatedassistancetosolve bottlenecksin ? Development ? QualityAssurance ? Maintenance by ? Product-&Systemdefinition ? TechnologyIntegration TMGi-tec ? Tools ? System-/Projectmanagement

TMGi-tecGmbH||Pfinztalstrasse90D-76227Karlsruhe Tel.:++4972182806-0| Fax:++4972182806-10 E-Mail:[email protected]| WEB:www.tmgitec.de

PROFIBUStraining Salescenterfor servicetools

Engineeringsupport Installationinspection &commissioning Productdevelopment

Remote&on-site Productcertification troubleshooting

ThePROFIBUSandPROFInet PROFIBUS CompetenceCenterandTestLab inFürthisyourpartnerfor -Demonstration Generaltechnicalsupport -Training ASICsupport PROFIBUSCertificationtestsfor -Consultation DP-V0,DP-V1,DP-V2 PA,PROFIsafe JapanesePROFIBUSCompetenceCenter(JPCC) PROFInetCertifications c/oYaskawaSiemensAutomation&DrivesCorp. Address: 3-1Ariake,Koto-ku,Tokyo ComDeC 135-8072Japan Tel.81-3-3570-3034Fax.81-3-3570-3063 WürzburgerStrasse121 E-mail:[email protected] 90766Fürth/Germany Youcanreachusby phone:+49(0)9117502080/2074,fax:+49(0)9117502100 e-mail:[email protected]

ChinesePROFIBUSCompetenceCenter ThePROFIBUSInterfaceCenter takeschargeofconsultation,training, inJohnsonCity,Tennessee,USA, isanaccreditedCompetenceCenter applictionandpopularizationof andTestLabforbothPROFIBUSandPROFInet. PROFIBUStechnologyinChina. Weprovide: -Generaltechnical&developmentsupport EmbeddedPROFIBUSCommunication -PROFIBUSASICsupport Bridge,theInterfaceoffersasolutionof developingPROFIBUSproductsquickly PROFIBUSCertificationTestingfor: intheOEMwayforenterprises. -DP-V0Master&Slave -DP-V1Master&SlaveincludingAlarms -PROFInet PROFIBUSRS232/485Bridge-connecting devicesof232/485interfacewithPROFIBUS- otherfieldbusdevicesaswell. PROFIBUSInterfaceCenter OneInternetPlaza POBox4991 ChinesePROFIBUSCompetenceCenter JohnsonCity,TN37602-4991 No.1Jiaochangkou,Deshengmenwai Phone:+1423.262.2576FAX:+1423.262.2103 100011Beijing,China e-mail:[email protected] Tel.:+861082078264Fax:+861082078264 [email protected] e-mail:[email protected]: www.c-profibus.com.cn

Commitment

We are and will remain the world’s leading organization in the field of digital networking for industrial and process automation, serving our customers, our members and the press with the best solutions, benefits and information.

We are committed to setting and protecting the standards for open communication and control in the automation and process market.

Introduction

From the outset, the field of auto- around system integration, engi- tion technology in the world of mation has been subject to con- neering and, in particular, the ap- automation opens up many new tinuous change. Not so long ago, plication profiles. These profiles prospects for global data commu- this change was limited to the pro- have made PROFIBUS the only nication between automation sys- duction area of a company. In pro- fieldbus that provides comprehen- tems. In pursuit of this objective, duction, the implementation of sive both factory and process PROFIBUS is enhanced by the fieldbus technology has meant automation. Ethernet-based communication considerable innovation, enabling standard PROFInet. the migration from centralized to Additionally, Information Technol- decentralized automation systems. ogy (IT) increasingly determines The use of open standards rather This has been the PROFIBUS ob- development in today´s world of than proprietary solutions ensures jective for more than 10 years. automation. Modern fieldbus sys- long-term compatibility and ex- tems have adopted IT principles pandability - in other words - pro- In those 10 years PROFIBUS has and are achieving greater consis- tection of existing investment. This become the world market leader in tency with the corporate manage- is a matter of key importance to the fieldbus technology. In spite of the ment level. In this respect, indus- PROFIBUS User Organization. The outstanding success of recent trial automation is following the de- continuous development of PRO- years, PROFIBUS development velopment trends of the office FIBUS technology provides continues with undiminished en- world, where IT has long since left members with a long-term perspec- thusiasm and energy. Initially the its mark, radically transforming in- tive. focus was on communication tech- frastructure, systems and proc- nology. Current activities center esses. The integration of informa-

Contents

1. Communication in Automation ...... 1 6. System Profiles...... 23 1.1 Industrial Communication...... 1 1.2 Fieldbus Technology Terms ...... 2 7. Device Management ...... 25 1.3 International Standardization...... 3 7.1 GSD ...... 25 7.2 EDD ...... 26 2. PROFIBUS at a Glance...... 4 7.3 FDT/DTM Concept ...... 27 2.1 History...... 4 2.2 Market Position ...... 4 8. Quality Assurance ...... 28 2.3 Organization...... 4 8.1 Test procedure ...... 28 2.4 The PROFIBUS ”Tool Box” ...... 5 8.2 Conformance Certificate...... 28 2.5 PROFIBUS - The keys to success ...... 6 9. Implementation ...... 29 3. PROFIBUS Transmission and Communication ...... 7 9.1 Standard Components...... 29 9.2 Implementation of Interfaces ...... 30 3.1 Transmission Technology ...... 7 3.2 Communication Protocol DP ...... 10 10. PROFInet ...... 31 4. General Application Profiles ...... 17 10.1 The PROFInet Engineering Model ...... 31 10.2 The PROFInet Communications Model...... 32 4.1 PROFIsafe ...... 17 10.3 The PROFInet Migration Model...... 32 4.2 HART on PROFIBUS DP ...... 17 10.4 XML...... 32 4.3 Time Stamp...... 18 10.5 OPC and OPC DX...... 32 4.4 Slave Redundancy ...... 18 11. PROFIBUS International...... 33 5. Specific Application Profiles ...... 19 5.1 PROFIdrive ...... 19 5.2 PA Devices...... 20 5.3 Fluid Power ...... 21 5.4 SEMI Devices...... 22 5.5 Ident Systems ...... 22 5.6 Remote I/O for PA...... 22

Contents

This document describes the es- that, in spite of the care that has These chapters emulate the modu- sential aspects of PROFIBUS and been taken in the preparation of lar layout of PROFIBUS, from takes into account the level of this overview, only the PROFIBUS communication technology through technology available at the end of documents available on the Inter- application profiles to system pro- 2002. Its objective is to provide a net are definitive and binding. files. comprehensive description of the Please refer to them for more de- world's leading fieldbus system, tailed information. Chapters 7 to 9 are more practi- PROFIBUS, without becoming too cally oriented. They deal with sub- engulfed in specific details. Chapters 1 and 2 offer an intro- jects such as device management, duction to the principles of fieldbus implementation and certification. This brochure not only offers suffi- technology and their implementa- cient information to those with a tion with PROFIBUS. Chapter 10 presents the theory of basic knowledge and readers in- operation of PROFInet. terested in an overview, but it also Chapters 3 to 6 deal with the core Chapter 11 completes the bro- introduces experts to more exten- aspects of PROFIBUS and any chure with details of PROFIBUS In- sive specialized literature. In this repetition of subject matter dealt ternational and the PROFIBUS context, we would like to point out with in Chapter 2 is intentional for reasons of completeness. User Organization.

1. Communication in PROFIBUS fulfills these criteria adopted standards IEC 61158 and and offers an universal solution for IEC 61784. PROFIBUS is an inte- Automation both factory and process automa- gral part of these standards. tion. Recently, Ethernet-based commu- The communication capability of At the cell level programmable nication systems have emerged in devices and subsystems and con- controllers such as PLCs and IPCs, industrial automation. They offer sistent information methodology communicate with each other and wide-ranging options for communi- are indispensible components of with IT systems of the office world cations between the different levels future-oriented automation con- using standards such as Ethernet, of industrial automation and the of- cepts. Communications are in- TCP/IP, Intranet and Internet. This fice world. PROFInet is an example creasingly occuring horizontally at information flow requires large data of one such Ethernet-based com- the field level as well as vertically packets and a range of powerful munication system. through several hierarchical levels communication functions. simultaneously. Layered and coor- A need for the coordinated devel- dinated industrial communication As well as PROFIBUS, Ethernet- opment and distribution of these systems, such as PROFIBUS with based PROFInet offers a trendset- fieldbus systems in the market has lower-level interfacing to AS- ting solution for this purpose. seen the emergence of a number Interface and upper level interfac- of User Organizations comprising ing to Ethernet (over PROFInet) In the following PROFIBUS will be manufacturers, users and insti- (see Figure 1), offer ideal precondi- described in detail as the central tutes, such as the PROFIBUS User tions for transparent networking in connecting link for the information Organization (PNO) and its parent all areas of the production process. flow in the automation industry. For organization PROFIBUS Interna- information on AS-Interface please tional (PI) for PROFIBUS and reffer to the relevant literature. Fur- PROFInet technologies. 1.1 Industrial thermore PROFInet will be briefly presented in chapter 10. User benefits are the motivation Communication for the emergence and continual Fieldbuses are industrial com- At the sensor-actuator level development of fieldbus technol- munication systems that use a signals of binary sensors and ac- ogy. This ultimately manifests itself range of media such as copper ca- tuators are transmitted over a sen- as a reduction of the total cost of ble, fiber optics or wireless, with sor actuator bus. This provides a ownership, as well as an increase bit-serial transmission for coupling simple and cost-effective technol- in performance and quality im- distributed field devices (sensors, ogy where data and power are provement during the setup and actuators, drives, transducers, etc.) transmitted over a shared medium. operation of automation plants. The to a central control or management AS-Interface offers a suitable bus benefits are achieved during con- system. Fieldbus technology was system for this field of application. figuration, cabling, engineering, developed in the 80s with the aim documentation, assembly and At field level distributed devices of replacing the commonly used commissioning, as well as during such as I/O modules, transducers, central parallel wiring and prevail- production. An additional benefit is drive units, analysis devices, ing analog signal transmission achieved by the reduction of the to- valves or operator terminals, com- (4-20 mA- or +/- 10V interface) tal life-cycle costs in the form of municate with automation systems withdigital technology. Due, in easy modification and continuous over a powerful, real-time commu- parts, to the different industry- availability due to regular diagnosis nication system. Transmission of specific demands and preferred information, preventive mainte- the process data is cyclic, while proprietary solutions of large manu- nance, simple parameter assign- additional interrupts, configuration facturers, several bus systems with ment, consistent data flow and as- data and diagnosis data are trans- varying properties were established set management. mitted acyclically as required. in the market. The key technologies are now included in recently Fieldbuses increase the productiv- ity and flexibility of automated processes compared to conventional technology and they create Enterprise the basic prerequisite for the configuration of distributed automation systems.

Production Today PROFIBUS is used in virtu- Cell level ally all areas of automation, in factory automation and process auto- Field level mation, but also in traffic engineer- Automation ing, power generation and power distribution. Sensor/actuator level

Field communications Data communications

PROFInet IEC 61158/61784 PROFIBUS IEC 61158/61784 AS-Interface IEC 62026

Fig. 1: Communication in automation technology

PROFIBUS Technology and Application, October 2002 1

Sender Receiver Designation and function of the layers Interface to application program with application-oriented 7 7 Application layer commands (read, write) Representation (coding) of data for analysis and 6 6 Presentation layer interpretation in the next layer Establishing and clearing temporary station connections; 5 5 Session layer synchronization of communicating processes Controlling data transmission for layer 5 (transport errors, 4 4 Transport layer break down into packets) Establishing and clearing connections, avoiding network 3 3 Network layer congestion Description of bus access protocol (Medium Access 2 2 Data-link layer Control, MAC) including data security Definition of the medium (hardware), coding and speed of 1 1 Physical layer the data transmission Transmission medium

Fig. 2: The OSI reference model

and simplify the transmission proc- oriented services (that means with ess. handshake procedure and monitor- 1.2 Fieldbus Technology ing) and connectionless services. Terms Bus access control (MAC, Me- The second group includes multi- dium Access Control) is a specific cast and broadcast messages that The ISO/OSI reference model procedure that determines at which are sent either to a specific group describes communications be- point in time a station can send or to all stations. tween the stations of a communica- data. While active stations can start tion system. In order for it to run ef- the exchange of information, pas- Profiles are used in automation fectively, defined rules and transfer sive stations may only begin com- technology to define specific prop- interfaces need to be used for the munication when prompted by an erties and behavior for devices, communications protocol. In 1983, active station. device families or entire systems. the International Organization for Only devices and systems using a Standardization (ISO) developed A distinction is made between a vendor-independent profile provide the OSI reference model ("Open controlled, deterministic access interoperability on a fieldbus, Systems Interconnection Re- procedure with real-time capability thereby fully exploiting the advan- ference Model") for just this pur- (master-slave with PROFIBUS) tages of a fieldbus. pose. This protocol defines the and a random, non-deterministic elements, structures and tasks re- access procedure (CSMA/CD with Application profiles refer primarily quired for communication and ar- Ethernet). to devices (field devices, controls ranges them into seven layers with and integration tools) and comprise each layer building upon the layer Addressing is necessary to se- both an agreed selection of bus beneath (Fig. 2). Each layer has to lectively identify a station. For this communications and the specific fulfill specified functions within the purpose, station addresses are as- device application. This type of pro- communication process. If a com- signed either by an address switch file serves manufacturers as a munication system does not re- (hard addresses) or during pa- specification for the development of quire some of those specific func- rameter assignment during com- profile-conforming and interoper- tions, the corresponding layers missioning (soft addresses). able devices. System profiles de- have no purpose and are by- scribe classes of systems that in- passed. PROFIBUS uses layers 1, Communication Services fulfill clude functionality, program inter- 2 and 7. communication tasks of the station faces and integration tools. either cyclic or acyclic user data Communications Protocols communication. The number and define how two or more stations type of these services are criteria exchange data using message for the application area of a com- frames. A data frame contains dif- munications protocol. A distinction ferent fields for messages and con- is made between connection- trol information. The actual data IEC 61158 OSI field is preceded by the header in- Contents formation (source and destination document layer address and details of the subse- IEC 61158-1 Introduction quent message) and followed by Physical layer specification and service IEC 61158-2 1 the data security part containing definition check information with regard to IEC 61158-3 Data-link service definition 2 the correctness of the transmission IEC 61158-4 Data-link protocol specification 2 (fault recognition). IEC 61158-5 Application layer service definition 7 A feature of fieldbuses is that they IEC 61158-6 Application layer protocol specification 7 enable optimum transmission of small, time-critical data volumes Table 1: Breakdown of IEC 61158

2 PROFIBUS Technology and Application, October 2002

Physical Implementa- PROFIBUS is Type 3 and PROFI- Profile set Data link layer tion net Type 10. RS485 IEC 61158 notes that bus commu- IEC 61158 subsets; Plastic fiber nication (by definition) is only pos- asynchronous PROFIBUS Profile 3/1 Glass fiber transmission sible between devices that belong PCF fiber to the same protocol type. IEC 61158 subsets; Profile 3/2 synchronous MBP PROFIBUS IEC 61784 bears the title "Profile transmission Sets for Continuous and Discrete Manufacturing Relative to Fieldbus ISO/IEC8802-3 ISO/IEC Profile 3/3 PROFInet Use in Industrial Control Systems“. TCP/UDP/IP/Ethernet 8802-3 Assignment to IEC 61158 is established through the following intro- Table 2: Properties of the Communication Profile Family CPF 3 ductory comment: "This interna- (PROFIBUS) tional standard (i.e. IEC 61784) specifies a set of protocol specific 1.3 International and is broken down into 6 parts communication profiles based on Standardization that are designated 61158-1, IEC 61158, to be used in the de- 61158-2 etc. The contents of Part 1 sign of devices involved in commu- International standardization deal with introductory subjects, nications in factory manufacturing of a fieldbus system is necessary while the subsequent parts are ori- and process control“. for its acceptance, establishment ented towards the OSI reference IEC 61784 depicts which subsets and its benefits. PROFIBUS model (layers 1, 2 and 7); see of the total available set of "ser- achieved national standardization Table 1. vices“ and “protocols” specified in in 1991/1993 in DIN 19245, Part 1- IEC 61158 (and other standards) 3 and Europe-wide standardization The various parts of IEC 61158 de- are used by a specific fieldbus sys- in 1996 in EN 50170. fine, among other things, the numerous services and protocols for tem for communication. The field- Together with other fieldbus sys- communication between stations bus-specific "communication pro- tems, PROFIBUS has been stan- which are regarded as the total files“ determined in this manner are dardized in IEC 61158 since 1999. available set, from which a specific summarized in the "Communica- 2002 saw the completion of activi- selection (subset) is made for spe- tion Profile Families (CPF)“ accord- ties to update IEC 61158. In the cific fieldbus systems. ing to their implementation in the course of these activities, the latest individual fieldbus systems. PROFIBUS and PROFInet devel- The fact that a wide range of differ- The profile sets implemented with opments were incorporated in this ent fieldbus systems is available on PROFIBUS are summarized under standard. the market is acknowledged in IEC 61158 by the definition of 10 "field- the designation "Family 3“ with IEC 61158 bears the title "Digital bus protocol types“ with the desig- subdivisions 3/1, 3/2 und 3/3. Table 2 shows their assignment to Data Communication for Meas- nation Type 1 to Type 10. PROFIBUS and PROFInet. urement and Control – Fieldbus for Use in Industrial Control Systems“

PROFIBUS Technology and Application, October 2002 3

2. PROFIBUS ZVEI (Central Association for the gressive technology and the suc- Electrical Industry) agreed to sup- cess of its non-commercial PRO- at a Glance port a mutual technical concept for FIBUS User Organisation e.V. factory and process automation. (PNO), the trade body of manufac- PROFIBUS is an open, digital turers and users founded in 1989. A first step saw the specification of Together with the 22 other regional communication system with a wide the complex communications pro- PROFIBUS associations in coun- range of applications, particularly in tocol PROFIBUS FMS (Fieldbus tries around the world, and the in- the fields of factory and process Message Specification), which was ternational umbrella organization automation. PROFIBUS is suitable tailored to demanding communica- PROFIBUS International (PI) for both fast, time-critical application tasks. A further step in 1993 founded in 1995, this organization tions and complex communication saw completion of the specification now boasts more than 1,100 mem- tasks. for the more simply configured and bers worldwide. Objectives are the faster PROFIBUS DP protocol PROFIBUS communication is an- continuous further development of (Decentralized Periphery). This chored in the international stan- PROFIBUS technology and in- protocol is now available in three dards IEC 61158 and IEC 61784. creased acceptance worldwide. functionally scaleable versions DP- The application and engineering V0, DP-V1 and DP-V2. As well as sponsoring the wide aspects are specified in the gener- range development of technology ally available guidelines of the and its acceptance, PI also under- PROFIBUS User Organization. 2.2 Market Position takes additional tasks for the This fulfills user demand for manu- worldwide support of members facturer independence and open- Building on these two communica- (users and manufacturer) with ad- ness and ensures communication tions protocols, coupled with the vice, information and procedures between devices of various manu- development of numerous applica- for quality assurance as well as the facturers. tion-oriented profiles and a fast standardization of technology in in- growing number of devices, ternational standards. PROFIBUS began ist advance, ini- 2.1 History tially in factory automation and, PI forms the largest fieldbus user since 1995, in process automation. The history of PROFIBUS goes association in the world. This Today, PROFIBUS is the fieldbus back to a association venture pro- represents future opportunities and world market leader with more than ject supported by the public au- responsibility in equal measure, a 20% share of the market, approx. thorities, which began in 1987 in opportunity to continue creating 500,000 equipped applications and Germany. Within the framework of and establishing leading technolo- more than 5 million nodes. Today, this venture, 21 companies and in- gies that are useful to users and there are more than 2000 stitutes joined forces and created a responsibility for those at the head PROFIBUS products available from strategic fieldbus project. The goal of these user associations to be a wide range of manufacturers. was the realization and establish- unwavering in their endeavors to ment of a bit-serial fieldbus, the target openness and investment protection for PROFIBUS in the fu- basic requirement of which was the 2.3 Organization standardization of the field device ture. This commitment (see introduction) serves as the guiding prin- interface. For this purpose, the The success of PROFIBUS stems ciple for all concerned. relevant member companies of the in equal measures from its pro-

Application Profiles II PA PA for for SEMI SEMI Encoder V2.0 and V3.0 Encoder V2.0 and V3.0 RIO RIO PA Devices PA PROFIdrive PA Devices PA PROFIdrive Ident Systems Ident Systems Weighing & Dosing System Profiles 1…x Weighing & Dosing Integration Technologies

Application Common Application Profiles (optional): Profiles I PROFIsafe, Time Stamp, Redundancy, etc.

IEC 61158/61784 Communication Technologies PROFIBUS DP DP-V0...V2

Transmission RS485: NRZ Fiber: Glass Multi Mode MBP *): Manchester Bus Powered Technologies RS485-IS: Intrinsic Safety Optics: Glass Single Mode MBP-LP: Low Power PCF / Plastic Fiber MBP-IS: Intrinsic Safety • (GSD, EDD) Descriptions • Tools (DTM, Configurators) • Master Conformance Classes •etc.) (Comm-FB, FDT, Interfaces • Constraints • Descriptions (GSD, EDD) • Tools (DTM, Configurators) • Master Conformance Classes • Interfaces (Comm-FB,etc.) FDT, • Constraints

Fig. 3: Technical system structure PROFIBUS

4 PROFIBUS Technology and Application, October 2002

2.4 The PROFIBUS best known PROFIBUS versions protection type EEx-i for use in po- ”Tool Box” (Fig. 4). tentially explosive areas. The specified levels of voltage and cur- PROFIBUS has a modular design PROFIBUS DP is the main em- rent refer to the safety-relevant and offers a range of communica- phasis for factory automation; it maximum values that must not be tion technologies, numerous appli- uses RS485 transmission technol- exceeded in either individual de- cation and system profiles, as well ogy, one of the DP commu- vices or during interconnection in as device management tools. Thus nications protocol versions and one the system. In contrast to the PROFIBUS covers the diverse and or more application profile(s) typi- FISCO model (see Chapter 3.1.2), application-specific demands from cal of factory automation, such as which only has one intrinsically the field of factory and process Ident Systems or Robots/NC. safe source, in this case all stations automation. The number of in- represent active sources. stalled PROFIBUS plants are proof PROFIBUS PA is the main em- of the high acceptance of this field- phasis for process automation, The MBP transmission technology bus technology. typically with MBP-IS transmission (Manchester Coded, Bus Powered, technology, the communications previous designation "IEC 1158-2 - From the technological stand- protocol version DP-V1 and the Physics", see Chapter 3.1) is avail- point the lower level (communica- application profile PA Devices. able for applications in process tions) of the system structure of automation with a demand for bus Motion Control with PROFI- PROFIBUS (see Fig. 3) is based powering and intrinsic safety of de- on the aforementioned ISO/OSI BUS is the main emphasis for vices. Compared to the previously reference model. This intentionally drive technology using RS485 used procedure, the "Fieldbus In- gave an abstract description of the transmission technology, the com- trinsically Safe Concept“ (FISCO, communication steps without pro- munications protocol version DP- see Chapter 3.1.2), which was viding details of content/practical V2 and the application profile specially developed for intercon- implementation. Fig. 3 contains the PROFIdrive. nection of intrinsically safe fieldbus implementation of the OSI model devices, considerably simplifies PROFIsafe is the main emphasis (layers 1, 2 and 7) in PROFIBUS planning and installation. for safety-relevant applications with details on how the layers are (universal use for allmost all indus- individually implemented/specified. Fiber-optic transmission is suit- tries), using RS485 or MBP-IS able for use in areas with high elec- Specifications agreed between transmission technology, one of the tromagnetic interference or where manufacturers and users on spe- available DP versions for commu- greater network distances are re- cific device applications are ar- nication and the application profile quired (see chapter 3.1.3). ranged above layer 7 in application PROFIsafe. profiles I and II. 2.4.2 Communication Across several layers, the modular 2.4.1 Transmission system as shown in Fig. 3 has the Protocols Technologies following: At the protocol level, PROFIBUS There is a whole range of trans- • Functions and tools for device with DP and its versions DP-V0 to mission technologies available for description and integration DP-V2 offers a broad spectrum of PROFIBUS. (umbrella term: Integration options, which enable optimum communication between different Technologies, see Chapter 7) RS485 is the most commonly and applications. Historically speaking, used transmission technology. It FMS was the first PROFIBUS uses a shielded twisted pair cable • A range of standards (inter- communications protocol. and enables transmission rates up faces, master profiles; um- to 12 Mbit/sec. brella term: system profiles) FMS that primarily serve the realiza- (Fieldbus Message Specifica- The newly specified version tion) is designed for communication of uniform, standardized RS485-IS has been recently systems, see Chapter 6. tion at the cell level, where pro- specified as a 4-wire medium in grammable controllers, such as

From the user standpoint PROFIBUS presents itself in the form of different typical-application main emphases that are not specifically defined but have proven useful as a result of frequent applications. Each main emphasis results from a typical (but not specifically defined) combination of modular elements from the groups "transmission technology", "communications protocol" and "application profiles". The following examples explain this principle using the Fig. 4: Typical, application-oriented features of PROFIBUS

PROFIBUS Technology and Application, October 2002 5

PLCs and PCs primarily communi- cial features of field devices, con- • PROFIBUS offers plant manu- cate with each other. It was the trols and methods of integration facturers and operators an in- forerunner of PROFIBUS DP. (engineering). The term profile dustry-wide, universal, open ranges from just a few specifica- technology. DP tions for a specific device class (Decentralized Periphery) is the through comprehensive specifica- • PROFIBUS is a key factor in simple, fast, cyclic and determinis- tions for applications in a specific noticeably reducing costs in tic process data exchange between industry. The generic term used for the field of machine and plant a bus master and the assigned all profiles is application profiles. engineering. slave devices. The original version, designated DP-V0, has been ex- A distinction is then drawn between • PROFIBUS has consistently panded to include version DP-V1, general application profiles with and logically expanded its ap- offering acyclic data exchange be- implementation options for different plication area while taking into tween master and slave. A further applications (this includes, for ex- account the demands of the version DP-V2 is also available, ample, the profiles PROFIsafe, respective application fields. which provides for direct slave-to- Redundancy and Time Stamp), This ensures optimum support slave communication with an specific application profiles, of industry-specific applica- isochronous bus cycle. which are developed for a specific tions. application, such as PROFIdrive, SEMI or PA Devices, and system • PROFIBUS means optimum The Bus Access Protocol, and master profiles, which de- integration in many automation layer 2 or the data-link layer, describe specific system performance and engineering systems for fines the master-slave procedure that is available to field devices. users due to its overall accep- and the token passing procedure tance and widespread use. for coordination of several masters PROFIBUS offers a wide range of on the bus (Fig. 5). The tasks of such application profiles, which al- • PROFIBUS has pursued the layer 2 also include functions, such low application-oriented implemen- stabilization and broad accep- as data security and the handling tation. tance of communication plat- of data frames. forms, the further development 2.5 PROFIBUS - of application profiles and the connection of industrial auto- The keys to success The Application Layer, Layer 7, mation to the IT world of corpo- defines the application layer and The success of PROFIBUS, its rate management. forms the interface to the applica- world market leadership is deter- tion program. It offers various ser- mined by many factors: vices for cyclic and acyclic data exchange.

2.4.3 Profiles

Profiles are the specifications defined by manufacturers and users regarding specific properties, performance features and behavior of devices and systems. Profile specifications define the parameters and behavior of devices and systems that belong to a profile family built around to profile-conformance development, which facilitate device interoperability and, in some in- stances, device interchangeability on a bus. Profiles take into account application and type-specific spe- Fig. 5: PROFIBUS configuration with active masters and slaves

6 PROFIBUS Technology and Application, October 2002

3. PROFIBUS fect on stations already in opera- When connecting the stations, al- tion. ways ensure that the data lines are Transmission and not reversed. Always use a Communication One new option is the ability of shielded data line (type A is RS485 to also operate in intrinsi- shielded) to ensure high interfer- cally safe areas (RS485-IS, see ence immunity of the system explanation at the end of this sec- 3.1 Transmission against electromagnetic emissions. tion). The shield should be grounded on Technology both sides where possible and Characteristics of RS485 In the ISO/OSI reference model, large-area shield clamps should be Various transmission rates can used for grounding to ensure good layer 1 defines the method of be selected between 9.6 Kbit/s and "physical" data transmission, i.e. conductivity. Furthermore, always 12 Mbit/s. One uniform speed is ensure that the data line is laid electrical and mechanical. This in- selected for all devices on the bus cludes the type of encoding and separately and, where possible, when commissioning the system. away from all power cables. Never the transmission standard used Up to 32 stations can be con- (RS485). Layer 1 is called the use spur lines for transmission nected. The maximum permissible rates ≥ 1.5 Mbit/s. physical layer. line length depends on the transmission rate. These and other Commercially available connectors PROFIBUS provides different properties are summarized in support direct connection of the in- versions of layer 1 as a transmis- Table 4. coming and outgoing data cable in sion technology (see Table 4). All the connector. This eliminates the versions are based on international need for spur lines and the bus standards and are assigned to Installation instructions for connector can be connected and PROFIBUS in both IEC 61158 and RS485 disconnected to the bus at any time IEC 61784. Topology without interrupting data communi- All devices are connected in a bus cations. The type of connector Transmission Range per structure (line). Up to 32 stations suitable for RS485 transmission Rate Segment (masters or slaves) can be con- technology depends on the degree [KBit/s] [m] nected in a single segment. The of protection. A 9-pin D-Sub con- 9.6; 19.2; 45.45; 1200 beginning and end of each seg- nector is primarily used for protec- 93.75 ment is fitted with an active bus tion rating IP 20. For IP 65/67 there 187.5 1000 terminator (Fig. 6). Both bus termi- are three common alternatives: 500 400 nators have a permanent power 1500 200 supply to ensure error-free opera- • M12 circular connector in ac- 3000; 6000; 12000 100 tion. The bus terminator is usually cordance with IEC 947-5-2 switched in the devices or in the The values refer to cable type A connectors. If more than 32 sta- • Han-Brid connector in accor- with the following properties: tions are implemented or there is a dance with DESINA recom- Impedance 135 to 165 Ω need to expand the network area, mendation Capacity ≤ 30 pf/m repeaters must be used to link the • Siemens hybrid connector individual bus segments. Loop resistance ≤ 110 Ω/km The hybrid connector system also Wire diameter > 0.64 mm Cables and Connectors Core cross-section > 0.34 mm2 provides a version for the trans- Different cable types (type designa- mission of data using fiber optics tion A - D) for different applications and 24 V working voltage for pe- Table 3: Transmission rate and are available on the market for range for cable type A ripherals over copper cable in a connecting devices either to each shared hybrid cable. other or to network elements (segment couplers, links and repeat- Problems with data transmission in 3.1.1 RS485 Transmission ers). When using RS485 transmis- PROFIBUS networks can usually Technology sion technology, PI recommends be attributed to incorrect wiring or the use of cable type A (see data in installation. These problems can RS485 transmission technology is Table 3). often be solved using bus test de- simple and cost-effective and pri- vices, which are able to detect marily used for tasks that require "PROFIBUS" cables are offered by many typical wiring errors even be- high transmission rates. Shielded, a wide range of manufacturers; PI fore commissioning. twisted pair copper cable with one particularly recommends the fast- conductor pair is used. connect system which, when used For a list of suppliers of the many with a suitable cable and special different connectors, cables, re- RS485 transmission technology is stripping tool, allows fast, reliable peaters, bus test devices men- easy to use. No expert knowledge and extremely simple wiring. tioned here, please refer to the is required for installation of the PROFIBUS online Product Catalog cable. The bus structure allows ad- (www.profibus.com). dition or removal of stations or the step-by-step commissioning of the RS485-IS system without influencing other There has been great demand stations. Subsequent expansions among users to support the use of (within defined limits) have no ef-

PROFIBUS Technology and Application, October 2002 7

VP (6) ing attributes Station 1 Station 2 • "Manchester Coding (M)", and 390 Ω

Data line • "Bus Powered", (BP). RxD/TxD-P (3) (3) RxD/TxD-P RxD/TxD-P (3)

DGND (5) (5) DGND This term replaces the previously 220 Ω VP (6) (6) VP common terms for intrinsically safe

Data line RxD/TxD-N (8) (8) RxD/TxD-N RxD/TxD-N (8) transmission "Physics in accor-

Shielding dance with IEC 61158-2", "1158-2", Protective Protective 390 Ω etc. The reason for this change is ground ground that, in its definitive version, the DGND (5) IEC 61158-2 (physical layer) describes several different connection Wiring Bus termination technologies, including MBP technology, not being therefore unam- Fig. 6: Wiring and bus termination for RS485 transmission technology biguos.

RS485 with its fast transmission maximum permissible current. MBP is synchronous transmission rates in intrinsically safe areas. with a defined transmission rate of An innovation of the RS485-IS 31.25 Kbit/s and Manchester cod- The PNO has addressed this task concept is that, in contrast to the ing. This transmission technology and worked out a guideline for the FISCO model that only has one in- is frequently used in process auto- configuration of intrinsically safe trinsically safe source, all stations mation as it satisfies the key de- RS485 solutions with simple device now represent active sources. The mands of the chemical and petro- interchangeability. continuing investigations of the chemical industries for intrinsic testing agency lead us to expect safety and bus power using two- The specification of the interface that it will be possible to connect up wire technology. The characteris- details the levels for current and to 32 stations to the intrinsically tics of this transmission technology voltage that must be adhered to by safe bus circuit. all stations in order to ensure safe are summarized in Table 4. This functioning during operation. An means that PROFIBUS can also be electric circuit permits maximum used in potentially explosive areas currents at a specified voltage 3.1.2 Transmission in and be intrinsically safe. level. When connecting active Accordance with MBP sources, the sum of the currents of The term MBP stands for trans- all stations must not exceed the mission technology with the follow-

MBP RS485 RS485-IS Fiber Optic

Data transmission Digital, bit-synchronous, Digital, differential Digital, differential Optical, digital, NRZ Manchester encoding signals according signals according to RS485, NRZ to RS485, NRZ Transmission rate 31.25 KBit/s 9.6 to 12,000 KBit/s 9.6 to 1,500 KBit/s 9.6 to 12,000 KBit/s Data security Preamble,error-protected, HD=4, Parity bit, HD=4, Parity bit, HD=4, Parity bit, start/end delimiter start/end delimiter start/end delimiter start/end delimiter Cable Shielded, twisted pair Shielded, twisted pair Shielded, twisted Multimode glass fiber, copper copper, cable type A 4-wire, cable type A singlemode glass fiber, PCF, plastic Remote feeding Optional available over Available over Available over Available over signal wire additional wire additional wire hybrid line Protection type Instrinsic safety None Instrinsic safety None (EEx ia/ib) (EEx ib) Topology Line and tree topology Line topology with Line topology with Star and ring topology with termination; also in termination termination typical; line topology combination possible Number Up to 32 stations per Up to 32 stations per Up to 32 stations per Up to 126 stations per of stations segment; total sum of segment without segment; up to 126 network max. 126 per network repeater; up to 126 stations with repeater stations with repeater Number Max. 4 repeater Max. 9 repeater with Max. 9 repeater with Unlimited with signal of repeaters signal refreshing signal refreshing refreshing (time delay of signal)

Table 4: Transmission technologies (Physical Layer) at PROFIBUS

8 PROFIBUS Technology and Application, October 2002

Installation Instructions for pedance. When using a tree topol- to specify a supply unit and the line MBP ogy, all field devices connected to length for the selected cable type. the fieldbus segment are wired in The required current (=Σ power re- Connection technology parallel in the field distributor. In all quirements) is derived from the The intrinsically safe transmission cases, the maximum permissible sum of the basic currents of the technology MBP is usually limited spur line lengths must be taken into field devices connected in the re- to a specific segment (field devices account when calculating the over- spective segment plus, where ap- in hazardous areas) of a plant, all line length. In intrinsically safe plicable, a reserve of 9 mA per which are then linked to the RS485 applications, a spur line has a max. segment for the operating current segment (control system and engi- permissible length of 30 m. of the FDE (Fault Disconnection neering devices in the control Electronics). The FDE prevents room) via a segment coupler or Transmission Medium faulty devices permanently block- links (Fig. 7). A shielded two-wire cable is used ing the bus. as the transmission medium, see Segment couplers are signal con- Fig. 6. The bus trunk cable has a Joint operation of bus-powered and verters that modulate the RS485 passive line terminator at each externally fed devices is permissi- signals to the MBP signal level and end, which comprises an RC ele- ble. Please note that externally fed vice versa. They are transparent ment connected in series with R = devices also consume a basic cur- from the bus protocol standpoint. 100 Ω and C = 2 µF. The bus ter- rent over the bus terminator, which minator is already integrated in the must be taken into account accord- In contrast, links have their own in- segment coupler or link. When us- ingly when calculating the max. trinsic intelligence. They map all ing MBP technology, incorrect con- available feed current. the field devices connected to the nection of a field device (i.e. polar- MBP segment as a single slave in ity reversal) has no effect on the The FISCO model considerably the RS485 segment. There is no functionality of the bus as these simplifies the planning, installation limit to the transmission rate in the devices are usually fitted with an and expansion of PROFIBUS net- RS485 segment when using links, automatic polarity detection func- works in potentially explosive areas so that fast networks can also be tion. (see chapter 3.1.4). implemented using field devices with MBP connection. No. of Stations, Line Length 3.1.3 Fiber Optic Transmis- Network Topologies with The number of stations that can be sion Technology MBP connected to a segment is limited Tree or line structures (and any to 32. However, this number may Some fieldbus application condi- combination of the two) are net- be further determined by the pro- tions place restrictions on wire- work topologies supported by tection type selected and bus bound transmission technology, PROFIBUS with MBP transmis- power (if any). such as those in environments with sion. very high electromagnetic interfer- In intrinsically safe networks, both ence or when particularly large dis- In a line structure, stations are the maximum feed voltage and the tances need to be covered. connected to the trunk cable using maximum feed current are defined Fiber optic transmission over fiber tee adapters. The tree topology is within strict limits. But the output of optic conductors is suitable in such comparable to the classic field in- the supply unit is limited even for cases. The PROFIBUS guideline stallation method. The multi-core nonintrinsically safe networks. (2.022) for fiber optic transmission master cable is replaced by the specifies the technology available two-wire bus master cable, the field As a rule of thumb for determining for this purpose. When determining distributor retains its function of the max. line length, it suffices to these specifications, great care connecting the field devices and calculate the power requirements was naturally taken to allow prob- detecting the bus terminator im- of the connected field devices, and lem-free integration of existing PROFIBUS devices in a fiber optic network without the need to change the protocol behavior of PROFIBUS (layer 1). This ensures backward compatibility with existing PROFIBUS installations.

The supported fiber optic types are shown in Table 5. The transmission characteristics support not only star and ring topology structures, but also line structures.

In the simplest case, a fiber optic network is implemented using electrical/optical transformers that are connected to the device and the fiber optics over a RS485 interface. Fig. 7: Plant topology and bus powering of field devices using MBP transmission technology This allows you to switch between RS485 and fiber optic transmission

PROFIBUS Technology and Application, October 2002 9

within a plant, depending on the Boundary conditions for the application of FISCO circumstances. • Only one power source permitted per segment 3.1.4 The FISCO model • All stations must be approved in accordance with FISCO • The cable length must not exceed 1000 m (ignition protection The FISCO model (Fieldbus Intrin- class i, category a)/ 1900 m (ignition protection class i, category b) sically Safe Concept) considerably • The cable must satisfy the following values: simplifies the planning, installation R´= 15 ... 150 Ω/km and expansion of PROFIBUS networks in potentially explosive ar- L´= 0.4 ... 1mH/km eas. C´= 80 ... 200 nF/km • All combinations of power supply unit and field devices must ensure This model was developed in Ger- that the permissible input variables of any of the field devices (Ui, Ii many by the PTB ( Physikalisch and P ) must be above the, in case of a fault, maximum possible and Technische Bundesanstalt - Ger- i man Federal Technical Institute) approved output variables (U0, I0 and P0; in the US: Vmax, Imax and and is now internationally recog- Pmax) of the relevant supply unit. nized as the basic model for the operation of fieldbuses in poten- User benefits of FISCO tially explosive areas. • Plug & Play supported, even in hazardous areas The model is based on the specifi- • No system certification cation that a network is intrinsically • Interchangeability of devices or expansion safe and requires no individual in- of plant without time-consuming calculations trinsic safety calculations when the • Maximization of the number of connected devices relevant four bus components (field devices, cables, segment couplers and bus terminators) fall within • No power is fed to the bus 3.2 Communication predefined limits with regard to when a station is sending. Protocol DP voltage, current, output, inductance • Each segment has only one The communications protocol DP and capacity. The corresponding source of power, the supply (Decentralized Peripherals) has proof can be provided by certifica- unit. been designed for fast data ex- tion of the components through au- • Each field device consumes a change at field level. This is where thorized accreditation agencies, constant basic current of at central programmable controllers, such as PTB (Germany) or UL least 10 mA in steady state. such as PLCs, PCs or process (USA) and others. • The field devices act as a pas- control systems, communicate with If FISCO-approved devices are sive current sink. distributed field devices, such as I/O, drives, valves, transducers or used, not only is it possible to op- • Passive line termination is im- analysis devices, over a fast serial erate more devices on a single line, plemented at both ends of the connection. Data exchange with but the devices can be replaced bus trunk line. during runtime by devices of other the distributed devices is primarily • Networks in line, tree and star manufacturers or the line can be cyclic. The communication func- topology are supported. expanded - all without the need for tions required for this are specified time-consuming calculations or With bus power, the basic current through the DP basic functions system certification. So you can of at least 10 mA per device serves (version DP-V0). Geared towards simply plug & play - even in haz- to supply power to the field device. the special demands of the various ardous areas! You merely need to Communication signals are gener- areas of application, these basic ensure adherence to the aforemen- ated by the sending device, which DP functions have been expanded tioned rules (see "Installation in- modulates ± 9 mA to the basic cur- step-by-step with special functions, structions for MBP) when selecting rent. so that DP is now available in three supply unit, line length and bus versions; DP-V0, DP-V1 and DP- terminator. V2, whereby each version has its own special key features (see Fig. Transmission according to MBP 8). This breakdown into versions and the FISCO model is based on largely reflects the chronological the following principles: sequence of specification work as a result of the ever-increasing demands of applications. Versions V0 Fiber type Core diameter [µm] Range and V1 contain both "characteristics" (binding for implementation) Multimode glass fiber 62.5/125 2-3 km and options, while version V2 only Singlemode glass fiber 9/125 > 15 km specifies options. Plastic fiber 980/1000 < 80 m HCS® fiber 200/230 approx. 500 m

Table 5: Characteristics of optical fibers

10 PROFIBUS Technology and Application, August 2002

The key contents of the three ver- Functional sions are as follows: Levels DP-V2 DP-V0 provides the basic func- Data Exchange Broadcast (Publisher / Subscriber) Isochronous Mode (Equidistance) tionality of DP, including cyclic data plus extensions: Clock Synchronization & Time Stamps exchange as well as station diag- HARTonDP nosis, module diagnosis and chan- Up/Download (Segmentation) Redundancy nel-specific diagnosis. DP-V1 Acyclic Data Exchange between PC or PLC and Slave Devices plus extensions: DP-V1 contains enhancements Integration within Engineering: EDD and FDT geared towards process automa- Portable PLC Software Function Blocks (IEC 61131-3) Fail-Safe Communication (PROFIsafe) tion, in particular acyclic data Alarms communication for parameter as- DP-V0 Cyclic Data Exchange between PLC and Slave Devices signment, operation, visualization plus extensions: Device Features Device and alarm handling of intelligent GSD Configuration Device Features field devices, parallel to cyclic user Diagnosis Time data communication. This permits online access to stations using en- Fig. 8: Functionality of the PROFIBUS DP version with key features gineering tools. In addition, DP-V1 defines alarms. Examples for dif- of these characteristics (see sum- System Configuration ferent types of alarms are status mary in table 6). alarm, update alarm and a manu- and Device Types facturer-specific alarm. Transmission Speed DP supports implementation of DP only requires approx. 1 ms at both mono-master and multi- DP-V2 contains further enhance- 12 Mbit/s for the transmission of master systems. This affords a ments and is geared primarily to- 512 bits of input and 512 bits of high degree of flexibility during sys- wards the demands of drive tech- output data distributed over 32 sta- tem configuration. A maximum of nology. Due to additional function- tions. 126 devices (masters or slaves) alities, such as isochronous slave Fig. 9 shows typical DP transmis- can be connected to a bus. The mode and slave-to-slave communi- sion times, depending on the num- specifications for system configura- cation (DXB, Data eXchange ber of stations and the transmis- tion define the following: Broadcast) etc., the DP-V2 can sion rate. When using DP, input also be implemented as a drive bus and output data are transmitted in • number of stations for controlling fast movement se- a single message cycle. With DP, quences in drive axes. • assignment of station ad- user data is transmitted using the dresses to the I/O addresses, SRD Services (Send and Receive The various versions of DP are • data consistences of I/O data, specified in detail in the IEC 61158. Data Service) of layer 2. • the format of diagnosis mes- The following explains the key Diagnosis Functions characteristics. sages and The comprehensive diagnosis • the bus parameters used. functions of DP enable fast location of faults. The diagnosis messages Device Types 3.2.1 Basic Functions are transmitted over the bus and Each DP system is made up of 3 DP-V0 collected at the master. These different device types. messages are divided into three The central controller (master) levels: DP Master Class 1 (DPM1) This is a central controller that cy- • reads input information from Device-Specific Diagnosis clically exchanges information with the slaves cyclically and Messages on the general readi- the distributed stations (slaves) at a ness for service of a station, such specified message cycle. Typical • writes output information to the as "Overheating", "Undervoltage" DPM1 devices are programmable slaves cyclically. or "Interface unclear". logic controllers (PLCs) or PCs. A DPM1 has active bus access with The bus cycle time should be Module-Related Diagnosis shorter than the program cycle time which it can read measurement These messages indicate whether data (inputs) of the field devices of the central automation system, a diagnosis is pending within a which is approx. 10 ms for many and write the setpoint values (out- specific I/O subdomain of a station puts) of the actuators at fixed applications. However, a faster (for example 8-bit output module). data throughput alone is not times. This continuously repeating enough for successful implementa- Channel-Related Diagnosis cycle is the basis of the automation tion of a bus system. Simple han- These messages indicate the function. dling, good diagnosis capabilities cause of a fault related to an indi- and interference-proof transmission vidual input/output bit (channel), technology are also key factors. DP such as "Short-circuit at output". provides an optimum combination

PROFIBUS Technology and Application, October 2002 11

DP Master Class 2 (DPM2) Bus access • Token passing procedure between masters Devices of this type are engineer- and data passing between masters and slaves ing, configuration or operating de- • Mono-master or multi-master system option vices. They are implemented dur- Master and slave devices, max. 126 stations ing commissioning and for mainte- • nance and diagnosis in order to on one bus configure connected devices, Communication • Peer-to-peer (user data communication) or evaluate measured values and pa- multicast (control commands) rameters and request the device • Cyclic master-slave user data communication status. A DPM2 does not have to Operating states • Operate be permanently connected to the Cyclic transmission of input and output data bus system. The DPM2 also has • Clear active bus access. Inputs are read, outputs remain in fail-safe state Slaves • Stop A slave is a peripheral (I/O de- Diagnosis and parameter assignment, no vices, drives, HMIs, valves, trans- user data transmission ducers, analysis devices), which Synchronization • Control commands enable the reads in process information synchronization of inputs and outputs and/or uses output information to • Sync mode intervene in the process. There are Outputs are synchronized also devices that solely process input information or output informa- • Freeze mode tion. As far as communication is Inputs are synchronized concerned, slaves are passive de- Functionality • Cyclic user data transfer between vices, they only respond to direct DP master and slave(s) queries. This behavior is simple • Dynamic activation/deactivation of individual and cost-effective to implement (in slaves; checking of slave configuration the case of DP-V0 it is already • Powerful diagnosis functions, completely included in the hard- 3 levels of diagnosis messages ware). • Synchronization of inputs and/or outputs • Optional address assignment for slaves over In the case of mono-master sys- the bus tems, only one master is active on • Maximum 244 bytes of input/output data per the bus during operation of the bus slave system. Figure 10 shows the sys- Protective func- • Message transmission at Hamming Distance tem configuration of a mono- tions HD=4 master system. The PLC is the • Watchdog control of DP slaves central control component. The detects failure of assigned master slaves are decentrally coupled to • Access protection for outputs of slaves the PLC over the transmission • Monitoring of user data communication with medium. This system configuration adjustable monitoring timer in master enables the shortest bus cycle Device types times. • DP master class 1 (DPM1) for example central programmable controllers, such as PLCs, In multi-master operation several PCs. masters are connected to one bus. • DP master class 2 (DPM2) They represent either independent for example engineering or diagnosis tools subsystems, comprising one • DP slave for example devices with binary or DPM1 and its assigned slaves, or analog inputs/outputs, drives, valves additional configuration and diagnosis devices. The input and out- Table 6: Overview of DP-V0 put images of the slaves can be read by all DP masters, while only one DP master (the DPM1 as- tion device. There are three main tion, inputs are read from the signed during configuration) can states: slaves and output information writ- write-access the outputs. ten to the slaves. Stop System Behavior No data communication between The DPM1 cyclically sends its In order to ensure a high degree of the DPM1 and the slaves. status to all its assigned slaves at device interchangeability among configurable intervals using a mul- Clear ticast command. devices of the same type, the sys- The DPM1 reads the input informa- tem behavior of DP has also been tion of the slaves and keeps the standardized. This behavior is de- The reaction of the system to a outputs of the slaves in a fail-safe fault during the data transfer phase termined primarily by the operating state ("0" output). state of the DPM1. of the DPM1, for example the Operate failure of a slave, is determined by This can be controlled either locally The DPM1 is in the data transfer the "auto clear" configuration pa- or over the bus from the configura- phase. In cyclic data communica- rameter.

12 PROFIBUS Technology and Application, October 2002

If this parameter is set to True, the DPM1 switches the outputs of all Bus cycle time [ms] assigned slaves to a fail-safe state the moment a slave is no longer 18 ready for user data transmission. The DPM1 subsequently switches 14 500 Kbit/s to the clear state. 10 If this parameter is set to False, the DPM1 remains in the operate state 1.5 Mbit/s 6 even in the event of a fault and the user can control the reaction of the 12 Mbit/s system. 2 2 10 20 30 Slaves

Cyclic Data Communication Fig. 9: Bus cycle times of a DP mono-master system. Boundary conditions: between the DPM1 and the each slave has 2 bytes of input and output data Slaves The slaves begin sync mode when slaves are fitted with monitoring Data communication between the they receive a sync command from mechanisms in the form of time DPM1 and its assigned slaves is the assigned master. The outputs monitors. The monitoring interval is automatically handled by the DPM1 of all addressed slaves are then defined during configuration. in a defined, recurring sequence frozen in their current state. During (see Fig. 11). The user defines the subsequent user data transmis- At the DP Master assignment of the slave(s) to the sion, the output data are stored at The DPM1 uses a DPM1 when configuring the bus the slave while the output states Data_Control_Timer to monitor the system. The user also defines remain unchanged. The stored data communication of the slaves. which slaves are to be in- output data are not sent to the out- A separate timer is used for each cluded/excluded in the cyclic user puts until the next sync command slave. The time monitor is tripped if data communication. is received. Sync mode is termi- no correct user data transfer is nated with the "unsync" command. executed within the monitoring in- Data communication between the terval. In this case, the user is noti- DPM1 and the slaves is divided In the same way, a freeze com- fied. If the automatic error handling into three phases: parameteriza- mand causes the addressed slaves (Auto_Clear = True) is enabled, the tion, configuration and data trans- to enter freeze mode. In this DPM1 exits the operate state, fer. Before the master includes a mode, the states of the inputs are switches the outputs of the as- DP slave in the data transfer frozen at their current value. The signed slaves to the fail-safe state phase, a check is run during the input data are not updated again and shifts to the clear mode. parameterization and configuration until the master sends the next phase to ensure that the configured freeze command. Freeze mode is At the Slave setpoint configuration matches the terminated with the "unfreeze" The slave uses the watchdog con- actual device configuration. During command. trol to detect errors of the master or this check, the device type, format transmission. If no data communi- and length information and the cation with the master occurs number of inputs and outputs must Protective Mechanisms within the watchdog control inter- also correspond. This provides the val, the slave automatically user with reliable protection against For safety reasons, it is necessary switches its outputs to the fail-safe parameterization errors. In addition to ensure that DP has effective pro- state. to user data transfer, which is tective functions against incorrect In addition, access protection is re- automatically executed by the parameterization or failure of quired for the outputs of the slaves DPM1, the user can also request transmission equipment. For this operating in multi-master systems. that new parameterization data are purpose the DP master and the sent to the slaves. This ensures that only the author-

Sync and freeze mode

In addition to the station-related user data communication, which is automatically handled by the DPM1, the master can also send control commands to all slaves or a group of slaves simultaneously. These control commands are transmitted as multicast commands and enable sync and freeze modes for event-controlled synchronization of the slaves. Fig. 10: PROFIBUS DP mono-master system

PROFIBUS Technology and Application, October 2002 13

into the categories alarms and the actual data acquisition (TI ) status messages (see Fig. 12). over control (Rx) through to the setpoint data output (TO), which usually extends over two bus cy- 3.2.3 Version DP-V2 cles. Slave-to-Slave Clock Control This function (a real-time master Communications (DXB) sends time stamps to all slaves This function enables direct and over the new connectionless MS3 time-saving communication bet- services, designed for this pur- ween slaves using broadcast pose) synchronizes all stations to a communication without the detour system time with a deviation of less over a master. In this case the Fig. 11: Cyclic user data than one millisecond. This allows slaves act as "publisher", i.e., the transmission in DP the precise tracking of events. This slave response does not go ized master has direct access. For is particularly useful for the acquisi- through the coordinating master, all other masters, the slaves pro- tion of timing functions in networks but directly to other slaves embed- vide an image of their inputs and with numerous masters. This facili- ded in the sequence, the so-called that can be read without access tates the diagnosis of faults as well "subscribers" (see Fig. 15). This rights. as the chronological planning of enables slaves to directly read data events. from other slaves and use them as their own input. This opens up the 3.2.2 Version DP-V1 Upload and Download possibility of completely new appli- (Load Region) cations; it also reduces response This function allows the loading of Acyclic data communications times on the bus by up to 90 %. The key feature of version DP-V1 any size of data area in a field de- is the extended function for acyclic Isochronous Mode vice with few commands. This en- data communication. This forms This function enables clock syn- ables, for example, programs to be the requirement for parameteriza- chronous control in masters and updated or devices replaced with- tion and calibration of the field de- slaves, irrespective of the bus load. out the need for manual loading vices over the bus during runtime The function enables highly precise processes. and for the introduction of con- positioning processes with clock firmed alarm messages. Transmis- deviations of less than one micro- sion of acyclic data is executed second. All participating device cy- parallel to cyclic data communica- cles are synchronized to the bus tion, but with lower priority. Figure master cycle through a "global con- 13 shows some sample communi- trol" broadcast message. A special cation sequences. The master sign of life (consecutive number) class 1 has the token and is able to allows monitoring of the synchroni- send messages to or retrieve them zation. Fig. 14 shows the available from slave 1, then slave 2, etc. in a times for data exchange (DX, fixed sequence until it reaches the green), access of a master class 2 last slave of the current list (MS0 (yellow) and reserve (white). The channel); it then passes on the tored arrow identifies the route from ken to the master class 2. This master can then use the remaining available time ("gap") of the pro- grammed cycle to set up an acyclic connection to any slave (in Figure 13 slave 3) to exchange records (MS2 channel); at the end of the current cycle time it returns the token to the master class 1. The acyclic exchange of records can last for several scan cycles or their "gaps"; at the end, the master class 2 uses the gap to clear the connection. Similarly, as well as the master class 2, the master class 1 can also execute acyclic data exchange with slaves (MS1 channel).

Additional available services are shown in Table 7. Extended diagnosis As a further function, the device- specific diagnosis of the DP-V1 Fig. 12: Configuration of diagnosis messages in DP-V0 and DP-V1 have been enhanced and divided

14 PROFIBUS Technology and Application, October 2002

blocks enabled for read/write access are also regarded as as- PROFIBUS-DP Token PROFIBUS-DP signed to the modules and can be Master Class 1 Master Class 2 addressed using slot number and index. The slot number addresses the module and the index addresses the data blocks assigned to a module. Each data block can be up to 244 bytes (see Fig. 16). In the case of modular devices, the slot number is assigned to the DP- Slave DP-Slave DP-Slave modules. The modules begin at 1 1 2 3 and are numbered in ascending contiguous sequence. The slot number 0 is for the device itself. Cycle: Slave1 Slave2 Slave3 Slave3 Compact devices are regarded as a unit of virtual modules. These Cyclic Access Acyclic Access can also be addressed with slot of Master 1 of Master 2 number and index.

Fig. 13: Cyclic and acyclic communication in DP-V1 Through the length specification in the read/write request it is also possible to read/write parts of a data block. When access to the Master data block was successful, the slave sends a positive read/write position controller cycle TM TM TM R1 R2 R3 R1 R2 R3 R1 R2 R3 response or may otherwise be able to classify the problem by means of global its negative response. control DP-cycle MSG S1DX DX

velocity controller cycle

Slave1..3 TO TI TO TI TO TI

Fig. 14: Isochronous mode Function Invocation which is also checked by the DPM1 Function Invocation services allow when the system starts up. to control (start, stop, return, re- start) of programs or call of func- The acyclic data communication is tions (for example acquisition of also based on this model. All data measured values) in a DP slave. PROFIBUS - DP 3.2.4 Addressing with Slot Master Class 1 and Index

When addressing data, PROFIBUS assumes that the physical structure of the slaves is modular or can be Output Input data via Broadcast structured internally in logical func- data tional units, so-called modules. This model is also used in the basic DP functions for cyclic data communication, where each mod- Publisher Subscriber Subscriber ule has a constant number of in- (e.g. light array) (e.g. drive) (e.g. drive) put/output bytes that are transmit- Slave Slave Slave ted in a fixed position in the user data telegram. The addressing procedure is based on identifiers, which characterize a module type as input, output or a combination of Slave-to-slave communications both. All identifiers combined produce the configuration of a slave, Fig. 15: Slave-slave data exchange

PROFIBUS Technology and Application, October 2002 15

Services for Acyclic Data Communication between the DPM1 and Slaves Read The master reads a data block from the slave Write The master writes a data block to the slave An alarm is transmitted from the slave to the master, which explicitly acknowledges receipt. The slave can Alarm only send a new alarm message after it has received this acknowledgment; this prevents any alarms being overwritten. Alarm_Ack- The master acknowledges receipt of an alarm to the nowledge slave A status message is transmitted from the slave to the Status master. There is no acknowledgment. Data transmission is connection-oriented over a MS1 connection. This is set up by the DPM1 and is closely linked to the connection for cyclic data communication. It can be used by the master that has parameterized and configured the respective slave.

Services for Acyclic Data Communication between the DPM2 and Slaves Initiate Setup and termination of a connection for acyclic data Abort communication between the DPM2 and the slave Read The master reads a data block from the slave Write The master writes a data block to the slave The master can write application-specific data (speci- Data_ Transport fied in profiles) acyclically to the slave and, if required, read data from the slave in the same cycle. Data transmission is connection-oriented over a MS2 connection. This is set up before the start of the acyclic data communication by the DPM2 using the Initiate service. The connection is then available for Read, Write and Data_Transport services. The connection is terminated correspondingly. A slave can maintain several active MS2 connections simultaneously. How- ever, the number of connections is limited by the resources available in the respective slave.

Table 7: Services for acyclic data communication

Fig. 16: Addressing with slot and index

16 PROFIBUS Technology and Application, October 2002

4. General • Timeout for incoming message can be found in the document frames and their acknowledg- "PROFIsafe, Profile for Safety Application Profiles ment. Technology", Order No. 3.092.

• Identifier between sender and General application profiles de- receiver ("password"). scribe functions and characteristics • Additional data security 4.2 HART on PROFIBUS DP that relate to more than just one (Cyclic Redundancy Check, In view of the large number of application. They can also be used CRC). in conjunction with specific applica- HART devices installed in the field, tion profiles. By skillfully combining these reme- the integration of these devices in dial measures in connection with a existing or new PROFIBUS sys- patented "SIL monitor" (monitoring tems is of key importance to most users. 4.1 PROFIsafe of the frequency of failed messages) PROFIsafe achieves safety The PROFIBUS "HART" specifica- classes up to SIL 3 and beyond. For considerable time, the distrib- tion offers an open solution for this uted fieldbus technology for factory PROFIsafe is a single-channel problem. It includes the benefits of and process automation was sub- the PROFIBUS communication ject to the restriction that safety software solution, which is implemented in the devices as an addi- mechanisms without any changes tasks could only be solved using required to the PROFIBUS protocol conventional technology in a sec- tional layer "above" layer 7 (see Fig. 17); the standard PROFIBUS and services, the PROFIBUS ond layer or distributed over spe- PDUs (Protocol Data Units) or the cial buses. With PROFIsafe, components, such as lines, ASICs or protocols, remain unchanged. state machines and functional PROFIBUS has created a compre- characteristics. hensive, open solution for safety- This ensures redundancy mode and retrofit capability. relevant applications that satisfies This specification defines a profile most known safety criteria. Devices with the PROFIsafe profile of PROFIBUS that is implemented can be operated in coexistence in the master and slave above PROFIsafe defines how fail-safe layer 7, thus enabling mapping of devices (emergency stop pushbut- with standard devices without restriction on the same cable. the HART client-master-server tons, light arrays, overfill cutouts, model on PROFIBUS. The coop- etc.) can communicate over PROFIsafe uses acyclic communi- eration of the HART Foundation on PROFIBUS with fail-safe control- cation and can be used with the specification work ensures lers so safely that they can be used RS485, fiber optic or MBP trans- complete conformity with the HART for safety-related automation tasks mission technology. This ensures specifications. up to KAT4 compliant with EN954, both fast response times (important AK6 or SIL3 (Safety Integrity for the manufacturing industry) and The HART-client application is in- Level). It implements safe commu- intrinsically safe operation (impor- tegrated in a PROFIBUS master nications over a profile, i.e. over a tant for process automation). and the HART master in a special format of user data and a PROFIBUS slave (see Fig. 19), special protocol. In process technology, it is only whereby the latter serves as a mul- necessary to provide and prepare tiplexer and handles communica- The specification has been jointly one standard device type for fail- tion to the HART devices. drawn up by manufacturers, users, safe or normal operation, as the standardization committees and in- fail-safe functionality can be con- For the transmission of HART spectorates (TÜV, BIA). It is based figured during application (SIL2 for messages, a communication chan- on the relevant standards, primarily operational reliability). nel has been defined that operates the IEC 61508, which address the independently of the MS1 and MS2 concerns of software development As a generic software driver, connections. An HMD (HART Mas- in particular. PROFIsafe is available for a wide ter Device) can support several cli- range of development and runtime ents. The number of clients de- PROFIsafe takes into account a environments. The specification pends on the implementation. number of error possibilities that can occur in serial bus communications, such as the delay, loss or repetition of data, incorrect sequences, addressing or corrupt data.

There are a range of remedial measures, the following of which have been selected for PROFIsafe:

• Consecutive numbering of safety telegrams.

Fig. 17: Fail-safe mode with PROFIsafe

PROFIBUS Technology and Application, October 2002 17

HART devices can be connected PROFIBUS master PROFIBUS slave HART device with the HMD to PROFIBUS over different components (PROFIBUS HART HART Guideline "PROFIBUS Profile for HART client application master server HART“ Order No. 3.102).

HART profile HART profile HART HART comm comm 4.3 Time Stamp 7 7 2 2 When recording timing functions in 1 1 networks, particularly those such HART communication as diagnosis or fault location, it is useful to be able to provide certain events and actions with a time PROFIBUS DP stamp, which enables precise time assignment. Fig. 19:Integration of HART devices into PROFIBUS DP For this purpose, PROFIBUS offers • Slave devices contain two dif- • No additional configuration of the time stamp profile. Precondition ferent PROFIBUS interfaces the backup slave required, is clock control in the slaves that are called primary and thus no need for complex through a clock master over MS3 backup (slave interface). tools. services. An event can be given a These may be either in a sin- precise system time stamp and • Complete monitoring of both gle device or distributed over read out accordingly. A concept of slave parts possible. two devices. graded messages is used. The • The slave device has no influ- message types are summarized • The devices are equipped with ence on the bus load and two independent protocol therefore on the dynamic re- stacks with a special redun- sponse of PROFIBUS. dancy expansion. • A redundancy communica- The redundancy of PROFIBUS tion (RedCom) runs between slave devices provides high avail- the protocol stacks, i.e. within ability, short reversing times, no a device or between two de- data loss and ensures fault toler- vices, that is independent of ance. Please refer to the corre- PROFIBUS and whose per- sponding document, the formance capability is largely PROFIBUS Guideline "Specifica- determined by the redundancy tion Slave Redundancy", Order No. reversing times. 2.212.

Fig. 18: Time stamp and alarm In normal mode, communications

messages are sent exclusively over the pri- Control System (Master) mary slave; only this slave is con- nmLife-List under the term "Alerts" and are di- figured, it also sends the diagnosis vided into high-priority "alarms" data of the backup slave. In the FDL_Status FDL_Status (these transmit a diagnosis mes- PROFIBUS PROFIBUS event that the primary slave fails (Primary) (Backup) sage) and low-priority "events". In the backup slave takes over its both cases, the master acyclically Redundancy Redundancy functions, either because it has de- Extensions RedCom Extensions reads (using the MS1 services) the tected the failure itself or because it time-stamped process values and was requested to do so by the Process Data alarm messages from the alarm master. In addition, the master Redundant Slave and event buffer of the field device monitors all slaves and sends a di- (see Fig. 18). Please refer to the agnosis message as soon as the Fig. 20: Slave redundancy in corresponding document, the backup slave fails and there is no PROFIBUS PROFIBUS Guideline "Time further redundancy. Stamp", Order No. 2.192. A redundant slave device can be operated on one PROFIBUS line 4.4 Slave Redundancy or, in the event of an additional line redundancy, on two PROFIBUS The installation of field devices with lines. The advantages of this re- redundant communication behavior dundancy solution for the user are is desired in many applications. For as follows: this reason, PROFIBUS has drawn up the specification for a slave- • Only one device version re- redundancy mechanism that de- quired to implement different scribes the following device redundancy structures. characteristics (see Fig. 20): • Master, line and slave redundancy are available independently of one another.

18 PROFIBUS Technology and Application, October 2002

5. Specific tion solutions is highly dependent ing on and off of bottle tops). The on the task of the drive. For this positioning tasks are passed to the Application Profiles reason, PROFIdrive defines six drive controller over PROFIBUS application classes, which cover and started. PROFIBUS stands out from other the majority of applications. fieldbus systems primarily due to The central motion control the extraordinary breadth of appli- With standard drives (class 1), (classes 4 and 5) enables the co- cation options. The PROFIBUS the drive is controlled by means of ordinated motion sequence of mul- concept has set new standards. a main setpoint value (for example tiple drives. The motion is primarily Not only has it developed specific rotational speed), whereby the controlled over a central numeric profiles that take into account key speed control is carried out in the control (CNC). PROFIBUS serves industry-specific user demands - it drive controller. to close the position control loop as has also successfully united all key well as synchronize the clock (Fig. In the case of standard drives aspects across all applications in a 21). The position control concept with technological function standardized and open fieldbus (Dynamic Servo Control) of this so- (class 2), the automation process system, thus ensuring full protec- lution also supports extremely so- is broken down into several sub- tion of existing investment. phisticated applications with linear processes and some of the auto- motors. Table 8 shows all current specific mation functions are shifted from PROFIBUS application profiles as the central programmable control- Distributed automation by means well as those pending. ler to the drive controllers. of clocked processes and elec- PROFIBUS serves as the technol- tronic shafts (class 6) can be im- ogy interface in this case. plemented using slave-to-slave communication and isochronous 5.1 PROFIdrive Slave-to-slave communication be- slaves. Sample applications in- tween the individual drive control- clude "electrical gears", "curve The PROFIdrive profile defines de- lers is a requirement for this solu- vice behavior and the access pro- discs" and "angular synchronous tion. processes". cedure to drive data for electric drives on PROFIBUS, from The positioning drive (class 3) PROFIdrive defines a device model simple frequency converters integrates an additional position as functional modules that operate through to highly dynamic controller in the drive, thus cover- together internally and which reflect servo-controls. ing an extremely broad spectrum of the intelligence of the drive system. applications (for example the twist- The integration of drives in automa- These modules are assigned ob-

Current status Designation Profile contents of PNO guideline V2 3.072 The profile specifies the behavior of devices and the access proce- PROFIdrive dure to data for variable-speed electrical drives on PROFIBUS. V3 3.172 The profile specifies the characteristics of devices of process engi- V3.0 PA devices neering in process automation on PROFIBUS. 3.042 The profile describes how handling and assembly robots are con- V1.0 Robots/NC trolled over PROFIBUS. 3.052 The profile describes the interfacing of simple human machine inter- V1.0D Panel devices face devices (HMI) to higher-level automation components. 3.082 The profile describes the interfacing of rotary, angle and linear en- V1.1 Encoders coders with single-turn or multi-turn resolution. 3.062 The profile describes the control of hydraulic drives over PROFIBUS. V1.5 Fluid power In cooperation with VDMA. 3.112 The profile describes characteristics of devices for semiconductor SEMI 3.152 manufacture on PROFIBUS (SEMI standard). Low-voltage The profile defines data exchange for low-voltage switchgear (switch- 3.122 switchgear disconnectors, motor starters, etc.) on PROFIBUS DP. The profile describes the implementation of weighing and dosage sys- Dosing/weighing 3.162 tems on PROFIBUS DP. The profile describes the communications between devices for identi- Ident systems 3.142 fication purposes (bar codes, transponders). The profile defines the implementation of liquid pumps on PROFIBUS Liquid pumps 3.172 DP. In cooperation with VDMA. Due to their special place in bus operations, a different device model Remote I/O for PA and data types are applied to the remote I/Os compared to the 3.132 devices PROFIBUS PA devices.

Table 8: The PROFIBUS specific application profiles

PROFIBUS Technology and Application, October 2002 19

Application Class 4 Physical Block (PB) A PB contains the characteristic Automation data of a device, such as device Technology name, manufacturer, version and Interpolation Pos.Control serial number, etc. There can only be one physical block in each de- Clock vice. Control Word + Speed Setpoint + ... Status Word + Actual Position... Clock synchronism Transducer Block (TB) A TB contains all the data required Drive Drive Drive for processing an unconditioned Closed Loop Speed Ctrl. Closed Loop Speed Ctrl. Closed Loop Speed Ctrl. signal delivered from a sensor for passing on to a function block. If no processing is required, the TB can be omitted. M M M Encoder Encoder Encoder Multifunctional devices with two or more sensors have a correspond-

Fig. 21: PROFIdrive, positioning with central interpolation and ing number of TBs. position control Function Block (FB) An FB contains all data for final jects that are described in the pro- typical for signal flow - from proc- processing of a measured value file and defined with regard to their ess sensor signals through to the prior to transmission to the control functions. The overall functionality preprocessed process value which system, or on the other hand, for of a drive is described by the sum is read out at the control system processing of a setting before the of its parameters. together with a measured value setting process. status. The various steps of infor- In contrast to other drive profiles, mation processing (signal chain) The following function blocks are PROFIdrive only defines the ac- and the status forming process are available: cess mechanisms to the parame- shown in Fig. 25. ters and a subset of approx. 30 Analog Input Block (AI) profile parameters, which include The PA devices profile is docu- An AI delivers the measured value fault buffers, drive controllers, de- mented in a general requirement from the sensor/TB to the control vice identification, etc. part containing the currently valid system. specifications for all device types All other parameters (which may and in device data sheets contain- Analog Output Block (AO) number more than 1,000 in coming the agreed specifications for An AO provides the device with the plex devices) are manufacturer- specific device classes. The PA value specified by the control sys- specific, which provide drive manu- device profile is available in version tem. facturers great flexibility when im- 3.0 and contains device data plementing control functions. The sheets for the following: Digital Input (DI) elements of a parameter are ac- A DI provides the control system cessed acyclic over the DP-V1 pa- • Pressure and differential with a digital value from the device. rameter channel. pressure Digital Output (DO) PROFIdrive V3 uses the version • Level, temperature and flow A DO provides the device with the DP-V2 as its communications pro- rate value specified by the control sys- tocol with its innovative slave-to- • Analog and digital inputs and tem. slave communication and isochro- outputs The blocks are implemented by the nous mode, see Chapter 3.2. Valves and actuators • manufacturers as software in the Both application profiles are avail- • Analyzers field devices and, taken as a able on the Internet: "Profiles for whole, represent the functionality of variable speed drives", V2, Order- The Block Model the device. As a rule, several No.: 3.072; "PROFIdrive Profile In process engineering it is com- blocks work together in an applica- Drive Technology", V3, Order-No.: mon to use blocks to describe the tion, see Fig. 22, which shows a 3.172. characteristics and functions of a simplified block structure of a multi- measuring point or manipulating functional field device. point at a certain control point and to represent an automation applica- The configuration corresponds to 5.2 PA Devices tion through a combination of these the division of a signal chain in two subprocesses: Modern process devices are intrin- types of blocks. The specification of PA devices uses this function sically intelligent and can execute The functionality of the first sub- part of the information processing block model to represent functional sequences as shown in Fig. 22. process "measuring/actuating prin- or even the overall functionality in ciple" (Fig. 25- calibration, lineari- automation systems. The PA De- The following three block types are zation, scaling) is in the trans- vices profile defines all functions used: ducer blocks, the functionality of and parameters for different the second subprocess "preproc- classes of process devices that are essing measured val-

20 PROFIBUS Technology and Application, October 2002

warning/alarm limits are exceeded or fallen below (see Fig. 24). Value Status A value status information item is added to the measured value, which delivers a statement of the quality of the measured value. There are three quality levels bad, uncertain and good and additional information is provided on a sub- status that is assigned to each quality level.

Fig. 22: Block structure of a field device (with multifunctionality) Fail-Safe Behavior ues/postprocessing settings" (Fig. block is a "module" in this context. The PA Device profile also pro- 21- filter, limit value control, fail- The PA Device profile offers a se- vides fail-safe characteristics. If a safe behavior, operating mode selection of function blocks for this fault has occurred in the measuring lection) is in the function blocks. purpose. Devices with a configured chain, the device output is set to a modularity are described as multi- user-definable value. Users can se- Specifications in the variable devices. lect between three different fail- PA Device Profile safe behavior types. Devices with Several It is only possible to show a selec- Process Variables Please refer to the relevant docu- tion of the specifications in brief. Process devices increasingly offer ment, the PROFIBUS Guideline For further details, please refer to several process variables, for ex- "Profile for Process Control De- the specification or the relevant lit- ample using several sensors or in vices", Order No. 3.042. erature, for example "PROFIBUS the form of derived variables. This PA" (Ch. Diedrich/ Th. Bange- is taken into account in the trans- 5.3 Fluid Power mann, Oldenbourg-Industrie- ducer blocks of the profile by dif- verlag). This profile describes data ex- ferentiating between Primary Value change formats and parameters for (PV) and Secondary Value (SV). Illustration of the Signal proportional valves, hydrostatic Chain Limit-Value Check pumps and drives and is based closely on the PROFIdrive defini- The profile PA Devices specifies Part of the information processing tions. Either a parameter channel the functions and parameters that transferred to the device is the on DP-V0 or acyclic communica- are related to each step of the sig- limit-value check. For this purpose, tion over DP-V1 are used for sup- nal chain, as shown in Fig. 25. As PA Devices offers corresponding plying device parameters. an example, Fig. 23 and Table 9 mechanisms for signalling when provide details of the step "calibration" and Fig. 24 shows the step "limit-value check". Parameter Parameter description

Addressing Parameters LEVEL_HI Range of measured filling level Blocks are determined by means of their start address and parameters LEVEL_LO through a relative index within the Section from the sensor measuring block; as a rule, these can be freely CAL_POINT_HI range with which the level range is selected by the device manufac- mapped. turer. For access to the parameters CAL_POINT_LO (for example using an operator tool) the device-specific block Table 9: Parameters for the calibration function structures are stored in the direc- tory of the device. Batch Parameter Sets Level Values of Values the sensor the Values of Values

For implementation of field devices sensor the Output in batch processes, the profile al- Upper limit in cm³ lows storage of several parameter sets even during the commission- SS Sensor ing phase. The current batch proc- Lower limit ess is then switched to the assigned parameter set during run- Lower Upper Sensor value time. calibration point calibration point Modular Devices With PROFIBUS a distinction is Sensor measured value Adaptation of measuring range Time made between compact and modular devices, whereby a function Fig. 23: Specification of the calibration function

PROFIBUS Technology and Application, October 2002 21

5.5 Ident Systems

Ident systems is a profile for barcode readers and transponder systems. These are primarily intended for extensive use with the DP-V1 functionality. While the cyclic data transmission channel is used for small data volumes to transfer status/control information, the acyclic channel serves the transmission of large data volumes that result from the information in the barcode reader or transponder. The definition of standard function blocks has facilitated the use of Fig. 24: Specification of the limit-value check function these systems and paves the way for the application of open solutions Please refer to the corresponding 5.4 SEMI Devices on completion of international document, the PROFIBUS Guide- standards, such as ISO/IEC 15962 line "Profile Fluid Power Technol- Some kind of devices used in proc- and ISO/IEC18000. ogy", Order No. 3.112. ess automation are, together with others, also applied in semiconductor manufacturing, such as 5.6 Remote I/O for PA vacuum pumps or flow meters. Sensor measured value Due to their largely (fine) modular Measured value status The organization "Semiconductor design, remote I/O devices are dif- Equipment and Materials Interna- ficult to bring in line with the "ideal" Calibration tional" did already specify a PA Device model. For this reason, branch-specific device standard they have a special place in the Linearization, scaling (SECS, Semiconductor Equipment field of distributed process automa- Communication Standard) to which tion. Furthermore, economic sensi- Filter the PROFIBUS Application Profile tivity also strongly influences the SEMI is compatible. selected device configurations Limit value control (modules, blocks, ...), resources SEMI is structured in 4 parts (Gen- (memory, records, ...) and func- Fail-safe behavior eral Definitions, Massflow Control- tions (for example acyclic access). lers, Vacuum Pressure Gauges For this reason a simplified device Operating mode selection and Vacuum Pumps). model has been defined and the quantity framework restricted. The Over the bus to the control system aim is to offer maximum support on the basis of cyclically exchanged data formats. Fig. 25: Signal chain in the PA device profil

22 PROFIBUS Technology and Application, October 2002

6. System Profiles

Profiles in automation technology define specific characteristics and behavior for devices and systems so that these are uniquely charac- terized (in classes or families) and are vendor-independent, thus supporting device interoperability and interchangeability on a bus.

Master Profiles for PROFIBUS describe classes of controller, each of which support a specific "subset“ of all the possible master function- alities, such as Fig. 27: System and application profiles (in correlation) • Cyclic communications rameters that are made avail- Standardized Function • Acyclic communications able to the field devices, Blocks (Communication • Diagnosis, alarm handling • application profiles require Function Blocks) • Clock control specific system parameters in To realize manufacturer independ- order to simplify their defined ent system profiles, it is necessary • Slave-to-slave communication, characteristics. to specify, additionally to the al- isochronous mode ready existing communications • Safety By using these profiles the device platform, an Application Program- manufacturers focus on existing or mer´s Interface (API, Fig. 27), us- specified system profiles and the ing standardized function blocks. system manufacturers can provide System Profiles for PROFIBUS the platforms required by the exist- While application programmers can go a step further and describe ing or specified device application usually access cyclic communica- classes of systems including the profiles. tion data (MS0 channel) over the master functionality, the possible process image of a control system, functionality of Standard Program PROFIBUS has realized a number in the past there was no system- Interfaces (FB in accordance with of system profiles based on tried neutral program interface for acy- IEC 61131-3, safety layer and and tested applications in the field, clic data. In view of the wide range FDT) and integration options (GSD, (see Fig. 26). These are expected of manufacturers and devices, EDD and DTM). Fig. 26 shows the to be stipulated in specifications in standards are needed to be estab- standard platforms available today. the near future and extended by lished in this area to enable inte- further profiles in keeping with fu- gration of different field devices In the PROFIBUS system, the ture demands. master and system profiles provide without specific communication the much needed counterpart to knowledge in the application pro- the application profiles (Fig. 27): grams of different control systems. For this purpose, the PNO has now • Master and system profiles specified its guideline "Communi- describe specific system pa- cation and Proxy Function Blocks according to IEC 61138-3". This guideline specifies function blocks in a " combinations of standards " that are based on the widely used ..... standard IEC 61131-3 (program- Application Profiles ming languages) and also use the PROFIBUS-defined communication are using one or more of these Master/System Profiles services of the IEC 61158. are supporting one ore more of these Application Profiles The guideline defines communica- Master/System Profiles tions blocks for Master Classes 1 and 2 as well as slaves and several auxiliary functions. The technological functionality of a field device Discrete Discrete e.g. can be addressed under a compact Manu- Manu- Motion Process Safety PG/PC identification, which is used consis- facturing facturing Control Master Lower Upper Class 2 tently by all blocks. All blocks also Range Range have a common concept for dis- playing errors with coding in accordance with IEC 61158-6.

Fig. 26: Master/system profiles for PROFIBUS The PLC manufacturers of the corresponding system classes/profiles

PROFIBUS Technology and Application, October 2002 23

offer these standard communication blocks ("Comm-FBs") in PLC- Device Type User- z.B. Proxy-FB specific "IEC libraries". The field Program (IEC 61131-3) Manager (DTM), (EDD – Interpreter) device manufacturers can respond by creating uniform proxy function Process Comm-FB Field-Device- Application Programmer's blocks, which can be used with all Image (IEC 61131 -3) Tool (FDT) Interface (API) control systems. MS0 MS1 MS2 Communications Platform Application Programmer´s PROFIBUS PROFIBUS Interface (API) In order to make it as easy as possible for application programmers PROFIBUS Communications to use the communication services, MS0 MS1 MS2 blocks or function calls are made Platform available in the standard programming language libraries. Together with the FDT interface, the PRO- Fig. 28: Application Programmer´s Interface, API FIBUS "Comm-FBs" expand the Application Programmer's Interface as shown in Fig. 28. PLC System A PLC System B 3 FD-M delivers Field Device Proxy FB Manufacturer Proxy Function Blocks (FD-M) C Library: Library: Proxy function blocks represent a Proxy FB CommFB 2 FD-M uses technological device function by Comm FB Proxy FB Comm FB providing all the necessary input and output parameters at the block C A 1 PLC-M delivers C interface. These proxy function Comm FB B blocks are usually created once by the field device manufacturers and can be implemented in the control 4 Programmer (D) uses systems of the relevant system Comm FB and Proxy FB classes/profiles without any special D C A D C B adjustment (see Fig. 29). Portability Proxy Comm Proxy Comm FB FB FB FB Application program Application program

Fig. 29: Portable function blocks

24 PROFIBUS Technology and Application, October 2002

7. Device Management PROFIBUS device are described in are optional, for example a communication feature list Sync_Mode_supported. A GSD re- (GSD) in a defined data format; the places the previously conventional Modern field devices provide a GSD is very much suited for simple manuals and supports automatic wide range of information and also applications. It is created by the checks for input errors and data execute functions that were previ- device manufacturer and is in- consistency, even during the con- ously executed in PLCs and control cluded in the delivery of the device. figuration phase. systems. To execute these tasks, the tools for commissioning, main- The application features of a Structure of a GSD tenance, engineering and parame- PROFIBUS device (device charac- terization of these devices require teristics) are described by means A GSD is divided into three sec- an exact and complete description of a universal Electronic Device tions: of device data and functions, such Description Language (EDDL). The as the type of application function, file (EDD) created in this manner is General Specifications configuration parameters, range of also provided by the device manu- This section contains information values, units of measurement, de- facturer. The interpreter based on vendor and device names, fault values, limit values, identifica- EDD is very much proven for ap- hardware and software release tion, etc. The same applies to the plications with medium complexity. versions, as well as the supported controller/control system, whose transmission rates, possible time For complex applications there is device-specific parameters and intervals for monitoring times and also the solution of mapping all de- data formats must also be made signal assignment on the bus con- vice-specific functions, including known (integrated) to ensure error- nector. the user interface for parameteriza- free data exchange with the field tion, diagnosis, etc., as software devices. Master Specifications component in a Device Type Man- This section contains all the mas- PROFIBUS has developed a num- ager (DTM). The DTM acts as the ter-related parameters, such as the ber of methods and tools ("integra- "driver" of the device opposite the maximum number of connectable tion technologies") for this type of standardized FDT interface, which slaves or upload and download op- device description which enable is implemented in the engineering tions. This section is not available standardization of device man- tool or in the control system. in slave devices. agement. The performance range of these tools is optimized to spe- Slave Specifications cific tasks, which has given rise to 7.1 GSD This section contains all slave- the term scaleable device integra- specific information, such as the tion. Therefore the tools are put to- A GSD is a readable ASCII text file number and type of I/O channels, gether in one specification with and contains both general and de- specification of diagnosis text and three volumes. vice-specific specifications for information on the available mod- communication. Each of the entries ules in the case of modular de- In factory automation, for historical describes a feature that is sup- vices. reasons, the GSD is used prefera- ported by a device. By means of bly, but the use of FDT increases keywords, a configuration tool It is also possible to integrate bit- as well. In process automation, de- reads the device identification, the map files with the symbols of the pending on the requirements, EDD adjustable parameters, the corre- devices. The format of the GSD is and FDT are used (see Fig. 30). sponding data type and the permit- designed for maximum flexibility. It ted limit values for the configuration contains lists, such as the trans- Methods of device description: of the device from the GSD. Some mission rates supported by the de- of the keywords are mandatory, for vice, as well as the option to de- The communication features of a example Vendor_Name. Others scribe the modules available in a modular device. Plain text can also be assigned to the diagnosis mes- Discrete Manufacturing • Controls • Parameterization at Start-up sages. (Factory Automation) • Binary Remote I/O • Simplest Handling • Fixed Configuration There are two ways to use the •Network GSD: Configuration • GSD for compact devices •Drives • In-process whose block configuration is • Functional Safety Measurement already known on delivery. GSD This GSD can be created completely by the device FDT Program EDD Interpreter manufacturer. • Device Specific Handling • Uniform Device Handling • Application Interface • Device Description • GSD for modular devices • Middle to high Complexity Language • Low to middle Complexity whose block configuration is not yet conclusively specified Continuous Manufacturing • Closed-loop Control on delivery. In this case, the (Process Automation) • Tool-based Parameterization & Diagnosis user must use the configura- • Device Tuning at Run-time tion tool to configure the GSD in accordance with the actual Fig. 30: Integration technologies at PROFIBUS module configuration.

PROFIBUS Technology and Application, October 2002 25

By reading the GSD into the con- Profile ID This also contains support mecha- figuration tool (into a PROFIBUS A special range of ID numbers (ge- nisms to configurator), the user is able to neric ID numbers) have been re- make optimum use of the special served for field devices for process • integrate existing profile de- communication features of the de- automation and drives respectively: scriptions in the device device. 9700h - 977Fh or 3A00h - 3AFFh. scription, All field devices corresponding ex- • allow references to existing Certification with GSD actly to the specifications of the objects so that only supple- The device manufacturers are re- PROFIBUS PA Devices profile ver- ments require description, sponsible for the scope and quality sion 3.0 or higher, or PROFIdrive of the GSD of their devices. Sub- • allow access to standard dic- version 3, may use ID numbers tionaries and mission of a GSD profile (contains from this special range. The speci- the information from the profile of a fication of these profile ID numbers • allow assignment of the device device family) or an individual de- has further increased the inter- description to a device. vice GSD (device-specific) is es- changeability of these devices. The Using the EDDL device manufac- sential for certification of a device. ID number to be selected for the turers can create the relevant EDD respective device depends on vari- file for their devices which, like the PNO Support ous factors for example in the case GSD file, supplies the device in- To support device manufacturers, of PA Devices on the type and formation to the engineering tool the PROFIBUS Web site has a number of existing function blocks. and then subsequently to the con- special GSD editor/checker avail- The ID number 9760H is reserved trol system. able to download, which facilitates for PA field devices that provide the creation and checking of GSD several different function blocks files. EDD application (multivariable devices). Special An EDD is a very versatile source The specification of the GSD file conventions also apply to the des- of information, for example formats is described in the follow- ignation of the GSD files of these ing PROFIBUS guideline GSD, or- PA field devices. These are de- • Engineering der No. 2.122. scribed in detail in the PA Devices • Commissioning profile. • Runtime New Development Stages The first profile ID number reserved • Asset Management of the communication functions of for PROFIdrive (3A00h) is used • Documentation and eCom- PROFIBUS are continually inte- during the DP-V1 connection merce grated in the GSD by the PNO. buildup to check that the master Thus, the keywords for DP-V1 can EDD advantages and slave are using the same pro- be found in the GSD Revision 3 An EDD provides significant advan- file. Slaves that positively acknowl- and those for DP-V2 in the GSD tages to both device users and de- edge this identifier support the DP- Revision 4. vice manufacturers. V1 parameter channel described in Manufacturer ID the PROFIdrive profile. All further The uniform user and operation in- Every PROFIBUS slave and every profile ID numbers serve to identify terface supports the user by master class 1 must have an ID vendor-independent GSD files. number. This is required so that a This enables the interchangeability • Reducing training expenses master can identify the types of of devices of different manufacturer • Reliable operation connected devices without the without the need for new bus con- • Only one tool for all applica- need for extensive protocol over- figurations. For example, the VIK- tions heads. The master compares the NAMUR mode with vendor- • Validation of the input data ID number of the connected de- independent PROFIdrive GSD is vices with the ID numbers specified defined as a component of the The device manufacturer is sup- in the configuration data by the PROFIdrive profile for the chemical ported by the fact, that developing configuration tool. Transfer of the industry. an EDD is very easy and cost ef- user data is not started until the fective correct device types with the correct station addresses are con- 7.2 EDD • Without specific knowledge, by nected to the bus. This ensures op- the device developer timum protection against configura- The GSD is inadequate for describ- • By using existing EDDs and tion errors. ing application-related parameters text libraries and functions of a field device (for • By universal suitability for sim- For an ID number for each device example configuration parameters, ple to complex devices type, device manufacturers must ranges of values, units of measurement, default values, etc.). This apply to the PROFIBUS User Or- An EDD also provides investment requires a more powerful descrip- ganization who also handle ad- protection to both users and manu- tion language, which has been de- ministration of the ID numbers. Ap- factures because an EDD is inde- veloped in the form of the univer- plication forms can be obtained pendent of operating systems and sally applicable Electronic Device from any regional agency easy to extent. or from the PROFIBUS Web site Description Language (EDDL). on the Internet. Above all, the EDDL provides the New Development Stages language means for the description As with the GSD, the EDDL will of the functionality of field devices. also be subject to upgrade that

26 PROFIBUS Technology and Application, October 2002

keep it in step with the continuous The FDT specification is currently MS VisualBasic. development of advancing device available as version 1.2. The speci- technology. Work is currently un- fication of FDT is contained in the With DTMs it is possible to obtain derway on a unique specification PROFIBUS guideline 2.162. direct access to all field devices for for dynamic semantics and for the planning, diagnosis and mainte- description of hardware modular Device Description as nance purposes from a central slaves. Software Component workstation. A DTM is not a stand- The specific functions and dialog of alone tool, but an ActiveX compo- The specification of the EDDL is an a field device for parameterization, nent with defined interfaces. integral component of the interna- configuration, diagnosis and main- tional standard IEC 61804. It is in- tenance, complete with user inter- User Benefits cluded in the PROFIBUS guideline face, are mapped in a software of FDT/DTM 2.152. component. This component is The FDT/DTM concept is protocol- called the DTM (Device Type Man- independent and, with its mapping ager) and is integrated in the engi- of device functions in software 7.3 FDT/DTM Concept neering tool or control system over components, opens up interesting the FDT interface. new user options. The existing description languages for configuration and parameteriza- A DTM uses the routing function of The concept incorporates integration have their limits. This becomes an engineering system for commu- tion options where they are most clear when, for example nicating across the hierarchical useful, in the areas of engineering, levels. Furthermore it uses its pro- diagnosis, service and asset man- • complex, non-standardized ject data management with agement - liberated from the spe- characteristics of intelligent versioning. It works as a "driver", cific communication technologies of field devices including the di- similar to a printer driver, which the the various fieldbuses and the spe- agnosis capabilities are to be printer supplier includes in delivery cific engineering environment of made useable for the plant op- and must be installed on the PC by automation systems. erator or the user. The DTM is generated by The FDT standard provides a basis the device manufacturer and is in- • in the "Optimization of assets" for integrated solutions from the cluded in delivery of the device. field, functions for preventative field to the tools and methods of maintenance or for mainte- corporate management. nance procedures are to be DTM generation supported. There are various options for gen- erating the DTM: • the operation of devices needs to be "encapsulated" in soft- • Specific programming in a ware (safety technology, cali- higher programming language. bration, etc). • Reuse of existing component or tools through their encapsu- These complex task areas, require lation as DTM. an "auxiliary tool" that allows device manufacturers to provide us- • Generation from an existing ers with expanded and also very device description using a specific characteristics of their field compiler or interpreter. devices in standardized form and • Use of the DTM toolkit of which at the same time allows the manufacturers of automation systems to integrate these field device characteristics in the control system over standardized interfaces.

The solution to this is the fieldbus- independent interface concept FDT/DTM (see Fig. 31), which was developed in a working group of the PNO and the ZVEI (Central As- sociation for the Electrical Industry) and made generally available. The FDT Interface The definition of a universal interface provides the ability to implement suitable created software components on all engineering or other integration platforms of automation systems fitted with this interface. Such an interface has been specified and designated Fig. 31: FDT/DTM concept FDT (Field Device Tool).

PROFIBUS Technology and Application, October 2002 27

8. Quality Assurance pared with the target behavior and the result is written to the protocol file. In order for PROFIBUS devices of different types and manufacturers Behavior in the Case of Fault, to correctly fulfill tasks in the auto- which simulates bus faults, such as mation process, it is essential to interruptions, short-circuits of the ensure the error-free exchange of bus line and power failure. information over the bus. The re- Addressability: the test device is quirement for this is a standard- addressed under three arbitrary compliant implementation of the addresses within the address communications protocol and ap- range and tested for error-free plication profiles by device manu- functionality. facturers. Diagnosis Data: the diagnosis To ensure that this requirement is data must correspond to the entry fulfilled, the PNO has established a in the GSD and the standard. This quality assurance procedure requires external activation of the whereby, on the basis of test re- diagnosis. ports, certificates are issued to devices that successfully complete Mixed Operation: combination the test . slaves are checked for correct Fig. 32: Device certification procedure functioning with an FMS and DP The aim of the certification is to master. provide users the necessary secu- The test procedure, which is the rity for error-free functionality dur- same for all test laboratories, is Interoperability test: the test de- ing the common operation of de- made up of several parts: vice is checked for interoperability vices of different manufacturers. To The GSD/EDD Check ensures that with the PROFIBUS devices of achieve this, the device undergoes other manufacturers in a multiven- rigorous practical testing in inde- the device description files comply with the specification. dor plant. This checks that the pendent test laboratories. This en- functionality of the plant is main- ables early detection of any misin- The Hardware Test tests the elec- tained when the test device is terpretations of the standards by tric characteristics of the added. Operation is also tested developers, thus allowing remedial PROFIBUS interface of the device with different masters. action by manufacturers before de- for compliance with the specifica- vices are implemented in the field. tions. This includes terminating re- Each step of the test is carefully Interoperability of the device with sistors, suitability of the imple- documented. The test records are other certified devices is also part mented drivers and other modules made available to the manufacturer of the test. Upon successful com- and the quality of line level. and the PROFIBUS User pletion of the test, the manufacturer Organization. The test report can apply for a device certificate. The Function Test examines the serves as the basis for issuing a bus access and transmission pro- certificate. Basis for the certification procedure tocol and the functionality of the (see Fig. 35) is the standard EN test device. The GSD is used to 8.2 Conformance Certificate 45000. The PROFIBUS User Or- parameterize and customize the ganization has approved manufac- test system. The black-box proce- Once a device has successfully turer-independent test laboratories dure is used during testing, which passed all the tests, the manufac- in accordance with the specifica- means that no knowledge is re- turer can apply for a certificate from tions of this standard. Only these quired of the internal structure of the PROFIBUS User Organization. test laboratories are authorized to the implementation. The reactions Each certified device contains a carry out device tests, which form generated in the test specimen and certification number as a reference. the basis for certification. their time ratios are recorded on The certificate is valid for 3 years The test procedure and sequence the bus monitor. If necessary, the but can be extended after undergo- for certification are described in the outputs of the test device are moni- ing a further test. tored and logged. guidelines No. 2.032 (DP slaves), The addresses of the test laborato- No. 2.062 (PA field devices) and The Conformity Test forms the ries can be obtained from the No. 2.072 (DP master). main part of the test. The object is PROFIBUS Web site. to test conformity of the protocol implementation with the standard. 8.1 Test procedure Essentially, the test deals with the:

A precondition for the test is the State machine: the PROFIBUS assigned ID number and a GSD protocol is defined in the form of a file, as well as an EDD for the de- state machine. All externally visible vice where applicable. state transitions are tested. The target behavior is summarized in programmable sequences. The actual behavior is analyzed, com-

28 PROFIBUS Technology and Application, October 2002

9. Implementation

This chapter contains instructions on how to implement the communications protocol and the interfaces in automation/field devices.

For the device development or implementation of the PROFIBUS protocol, a broad spectrum of standard components and development tools (PROFIBUS ASICs, PROFI- BUS stacks, monitor and commissioning tools) as well as services are available that enable device manufacturers to realize cost- effective development. A corresponding overview is available in the product catalog of the PRO- FIBUS User Organization (www.profibus.com/productguide.htm). For further details please use technical literature and, for expert advice, contact one of the PROFIBUS Fig. 33: Example for the implementation of a PROFIBUS slave Competence Centers. the chip and also require an These ASICs offer a universal in- During implementation of a additional controller and terface and operate together with PROFIBUS interface, please note common microcontrollers. A further that the certification refers to the • Protocol chips with integrated microcontroller. option is offered by microproces- overall device. Standard compo- sors with an integrated PROFIBUS nents are not subject to the certifi- The type of implementation version core. cation process as this does not largely depends on the complexity provide a guarantee for the end of the field device, and the per- Implementation of product device. However the qual- formance and functionality re- Complex Masters ity of the standard components quired. The following offers some In this form of implementation, the also plays an important role in the examples. time-critical parts of the PROFIBUS successful certification of devices. protocol are also implemented on a Implementation of protocol chip and the remaining Simple Slaves protocol parts implemented as 9.1 Standard Components The implementation of single-chip software on a microcontroller. Vari- ASICs is ideal for simple I/O de- ous ASICs of different suppliers are Interface Modules vices. All protocol functions are al- currently available for the imple- The use of a complete PROFIBUS ready integrated on the ASIC. No mentation of complex master de- interface module is ideal for a microprocessors or software are vices. They can be operated in low/medium number of devices. required. Only the bus interface combination with many common These credit card size modules im- driver, the quartz and the power microprocessors. plement the entire bus protocol. electronics are required as external They are fitted on the master board components. A corresponding protocol chip of the device as an additional mod- overview is available on the ule. Implementation of PROFIBUS website. For further in- Intelligent Slaves formation please contact the sup- Protocol Chips In this form of implementation, the pliers directly. In the case of high numbers of de- essential layer-2 parts of the PROFIBUS Stacks vices, an individual implementation PROFIBUS protocol are imple- Frequently, chips and the respec- on the basis of commercially avail- mented on a protocol chip and the tive protocol software (PROFIBUS able PROFIBUS basic technology remaining protocol parts imple- stacks) may originate from different components is recommendable, mented as software on a microcon- suppliers, positively increasing the whereby a distinction is made be- troller. In most of the ASICS avail- variety of solutions available in the tween able on the market all cyclic proto- market. col parts have been implemented, • Single chips, in which all pro- which are responsible for transmis- tocol functions are integrated Based on that, technically opti- sion of time-critical data. on the chip and which do not mized and cost effective products can be developed, which meet ap- require an additional controller, Alternatively, protocol chips with in- plication specific market require- terpreted controllers may be used, • Communications chips, ments, in accordance with the re- where part of the protocol for less which implement smaller or spective commitment of the PRO- time-critical data transmission can larger parts of the protocol on FIBUS User Organization. This be realized.

PROFIBUS Technology and Application, October 2002 29

This also proves the openness and must be paid to low power con- sion technology, please refer to the multi-vendor capability of sumption. technical PNO guideline No. 2.092. PROFIBUS which are not limited to specifications but also comprise As a rule, only a feed current of RS485 Transmission product implementations. 10-15 mA over the bus cable is Technology available for these devices, which For field devices that cannot be Pure software solutions are rare must supply the overall device, in- powered over the bus, it is possible because of their unfavorable cluding the bus interface and the to use the standard RS485 inter- cost/performance relation com- measuring electronics. face. This increases flexibility when pared with chip-oriented implemen- implementing the device as this Special modem chips are available tations. Therefore, they are used can then be connected to a PRO- to meet these requirements. These only for specific applications. FIBUS DP segment without a cou- modems take the required operat- pler or link. A corresponding overview of ing energy for the overall device PROFIBUS stacks that are avail- from the MBP bus connection and Key features of RS485 Technology able on the market is presented on make it available as feed voltage are its low interface costs and rug- the PROFIBUS website. For further for the other electronic components gedness. Data rates of 9.6 Kbit/s information please contact the re- of the device. At the same time, the to12 Mbit/s are supported without spective suppliers. digital signals of the connected pro- the need to implement any tocol chip are converted into the changes. bus signal of the MBP connection 9.2 Implementation of modulated to the energy supply. A As a further enhancement, the Interfaces typical configuration with a com- RS485 IS has been developed, mercially available roundboard is which offers an intrinsically safe MBP transmission shown in Fig. 36. version of the RS485. technology When implementing a bus-powered For further details on how to im- The RS485 modules are available field device with MBP transmission plement the bus connection for from various manufacturers and technology, particular attention field devices with MBP transmis- proven in millions of applications.

30 PROFIBUS Technology and Application, October 2002

10. PROFInet PROFInet components The basic approach of PROFInet is the application of the object model, PROFInet is a comprehensive already tried and tested in the software world, on automation technol- automation concept that has ogy. For this purpose, machines, plants and their parts are divided into emerged as a result of the trend in technological modules, each of which comprises mechchanical, electri- automation technology towards cal/electronical and application software. The functionality of the tech- modular, reusable machines and nological module is encapsulated in PROFInet components, which can plants with distributed intelligence. be accessed over universally defined "interfaces". The components can With its comprehensive design be combined over their interfaces according to the modular principle (uniform model for engineering, and interconnected to applications. runtime and migration architecture to other communication systems, In this context "components" means an encapsulated, reusable soft- such as PROFIBUS and OPC) ware unit. For the implementation of this component model, PROFInet PROFInet fulfills all the key de- uses the model most common in the PC world, the Microsoft Compo- mands of automation technology nent Object Model (COM), in its expansion for distributed systems for (DCOM). In this case, all the objects of a system are equal and, to all outward appearances, identical. • consistent communications from field level to corporate This type of distributed automation system enables the modular design management level using of plants and machines and supports reusability of plant and machine Ethernet, parts. • a vendor-independent plant- wide engineering model for the entire automation landscape, specification of manufac- nents to an application using the turer/customized functional expan- PROFInet engineering tool (con- • openness to other systems, sions. nection editor). To do this, the gen- • implementation of IT standards erated PROFInet components are and The PROFInet engineering model transferred to the connection editor distinguishes between the by importing their XML files and the • integration capability of programming of the control logics relationship is established over PROFIBUS segments without of the individual technological graphical lines. This allows plant- the need to change them. modules and the configuration of wide combination of distributed ap- the overall plant for an application. PROFInet is available as a specifi- plications (of different manufacturers) to an overall application (see cation and as an operating sys- As previously, programming of the Fig. 34). The decisive advantage of tem-independent source software. individual devices and their con- this is the fact that the communica- The specification describes all as- figuration and parameterization is tion no longer needs to be pro- pects of PROFInet: the object and carried out by the manufacturer grammed. Instead, the communica- component model, the runtime with manufacturer-specific tools. tion relationships between the communication, the proxy concept The software created during pro- components are established over and the engineering. PROFInet gramming is then encapsulated in lines, called interconnections. software covers all runtime com- the form of a PROFInet component munications. This combination of using the component editor inter- The interconnection information is specification and software as face that is also to be integrated in then downloaded to the device with source code enables simple and the tool. The component editor in- a simple mouse click. This means efficient integration of PROFInet in terface generates the component that each device knows its com- the broadest range of device oper- description in the form of an XML munication partners and relation- ating system environments. The file whose configuration and con- ships and the information to be ex- chosen path of preparing a source tents are defined in the PROFInet changed. software upon which all product specification. implementations are built presents an outstanding opportunity to en- The plant is configured by inter- sure the consistent quality of the connecting the PROFInet compo- PROFInet interface in products. The procedure ensures that any interoperability problems are reduced to a minimum.

10.1 The PROFInet Engineering Model

A vendor-independent engineering concept has been defined to enable user-friendly configuration of a PROFInet system. It is based on an engineering object model which enables the development of configuration tools as well as the Fig. 34: Creation and interconnection of components

PROFIBUS Technology and Application, October 2002 31

10.2 The PROFInet Communications Model

The PROFInet communications model defines a vendor- independent standard for communication on Ethernet with conventional IT mechanisms (runtime communications). It uses TCP/IP and COM/DCOM, the most common standards of the PC world. It provides direct access from the office world to the automation level and vice versa (vertical integration).

With PROFInet, the DCOM wire protocol, together with the aforementioned standards, defines the Fig. 36: PROFInet migration model data exchange between the components of different manufacturers implemented unchanged, thus pro- the OPC Foundation with the goal over Ethernet. Alternatively, there viding users with maximum invest- of developing a protocol for the ex- is also an optimized communica- ment protection. Proxy technology change of non-time-critical user tion mechanism available for appli- also allows integration of other data between automation systems cation areas with hard real time re- fieldbus systems. of different manufacturers and quirements. types (PLC, DCS, PC). Devices that are operated on 10.4 XML OPC DX is based on the existing Ethernet require the implementa- specification OPC DA (Data Ac- tion of communication mechanisms XML (EXtensible Markup Lan- cess). At the same time an engi- in accordance with the PROFInet- guage) is a flexible data description neering interface has been defined, standard (see Fig. 35). The con- language based on a simple ASCII which enables configuration of the nection technology required for the code. XML documents can be ex- connected systems. In contrast to link to Ethernet is available in changed with applications in a PROFInet, OPC DX is not object- protection classes IP 20 and number of ways, for example on orientated, but tag-orientated, i.e. IP65/67. diskette, by e-mail, using TCP/IP or the automation objects do not exist with HTTP over the Internet. as COM objects but as (tag) 10.3 The PROFInet names. XML is important in automation Migration Model technology for, among other things, OPC DX will enable the connection The integration of PROFIBUS parameter descriptions in FDT, as of different automation systems in segments in PROFInet is imple- import and export format for field a plant at the Ethernet level. How- mented using proxies (see Fig. 36). device parameters in engineering ever, it is not possible to access These assume a proxy function for tools or as a means of vertical inte- field level, so that existing fieldbus all the devices connected to PRO- gration (data exchange independ- systems and PROFInet are not in- FIBUS. This means that when re- ent of the operating system used). fluenced in any way. building or expanding plants, the entire spectrum of PROFIBUS de- 10.5 OPC and OPC DX vices, including products of PRO- FIdrive and PROFIsafe can be OPC is a standard interface intro- duced in 1996 for access to Win- dows-based applications in automation. The implementation of OPC enables the flexible, manufacturer-independent selection of components and their interconnection without the need for programming. OPC is currently based on the Microsoft DCOM model.

Since 2000, OPC data and OPC services are mapped in XML, which means that OPC data can even be exchanged between non- Windows platforms by means of readable XML documents.

Fig. 35: Device structure of PROFInet OPC DX (Data EXchange) is being developed within the framework of

32 PROFIBUS Technology and Application, October 2002

11. PROFIBUS ten very different and come from a broad spectrum of industries (par- International ticularly in the WGs) produce a considerable synergy effect and In order to ensure its maintenance, generate a rigorous exchange of information. This leads to innova- development and market domi- nance, open technology requires a dardization committees and tive solutions, effective use of resources and last but not least, a company-independent institute as associations. significant market advantage. a working platform. In 1989, the • Worldwide technical support of PROFIBUS User Organization companies through the Com- Working Groups e.V. (PNO) was founded to pro- petence Centers. The WGs with their 300 honorary mote PROFIBUS technology in this members make a key contribution very manner. It is a nonprofit trade • Quality assurance through de- to the success of PROFIBUS. body of manufacturers, users and vice certification. Fig. 37 shows how the 5 TCs are institutes. The PNO is a member of Organization broken down to deal with different PROFIBUS International (PI) PI has handed over the develop- areas. The further division into founded in 1995, which now boasts ment of PROFIBUS technology to more than 35 WGs allows very fo- 23 regional user organizations PNO Germany. The advisory cussed development work on spe- (Regional PROFIBUS Associa- committee of PNO Germany now cific technologies and industries. tions, RPA) and more than 1,100 controls the development activities. members including those in the The development teams are organ- All members are entitled to partici- US, China and Japan who repre- ized in 5 Technical Committees pate in the working groups and are sent the largest trade body in the (TCs) with more than 35 perma- thus able to take a proactive stance field of industrial communications nent Working Groups (WGs). In on further development. All new worldwide (Fig. 38). addition to this, there are also a work results are submitted to members for further comment be- The RPAs organize exhibitions and changing number of ad hoc WGs fore they are released by the advi- information seminars but take care that handle specific subjects limited sory committee. that new market demands are con- to certain time periods. The WGs with more than 300 experts draw sidered during future development Competence Centers work. up new specifications and profiles, deal with quality assurance and PI has approved 22 Competence Centers worldwide as well as 7 test Tasks standardization, work in standardi- laboratories for certification work. The key tasks of PI are as follows: zation committees and undertake effective marketing measures These facilities offer all manner of • Maintenance and development (trade fairs, presentations) for ex- advice and support to users and of PROFIBUS technology. panding PROFIBUS technology. manufacturers as well as carrying out tests for the certification of de- • Extending worldwide accep- The PI support center coordinates all ongoing events. vices. As part of PROFIBUS Inter- tance and use of PROFIBUS national, they offer their services technology. Membership company-neutral according to the • Investment protection for users Membership in the PNO is open to agreed documents of rules. and manufacturer through in- all companies, associations, insti- Competence Centers as well as fluencing control of standardi- tutes and persons who would like Test Laboratories are regularly zation. to play a constructive role in the checked with respect to their quali- development and acceptance of • Representation of members' fication by performing an approval PROFIBUS technology. The mu- interests with regards to stan- procedure specifically oriented to tual efforts of members who are of- their tasks. Current addresses can be found on the PI Web site. Documentation By way of further support, the PNO offers all users and manufacturers a wide and very comprehensive range of documentation. This is provided in English and divided into the following categories:

PROFIBUS Standard contains the basic PROFIBUS specification and a selection of other documents.

PROFIBUS Guidelines contains specifications on implementations, test procedures, installations, description languages, as well as ap- Fig. 37: Structure of the PROFIBUS User Organization plication-oriented specifications, such as Time Stamp or PROFInet.

PROFIBUS Technology and Application, October 2002 33

PROFIBUS profiles contains all approved profile specifications.

Technical overviews and catalogs The key themes of PROFIBUS are presented in numerous technical overviews from a marketing standpoint. The product catalog, containing more than 2000 PROFIBUS products and services, offers an excellent overview of the performance capability of the member companies of PROFIBUS.

The documents are available in PDF format on the PROFIBUS Web site. If required you can also obtain the documentation on CD- Fig. 38: PI Organization ROM.

A list of all available documentation can also be obtained from the PNO or on the PROFIBUS Web site.

34 PROFIBUS Technology and Application, October 2002

Index

A H Actuator/sensor level...... 1 Acyclic data communication ...... 11 HART ...... 17 Addressing...... 2 Addressing with slot and index...... 15 I AS-Interface...... 1 Ident systems...... 22 IEC B IEC 61158...... 3 Block model ...... 20 IEC 61784...... 3 Broadcast...... 2 Implementation ...... 29 Bus access control ...... 2 Installation instructions Installation instructions for MBP ...... 9 C Interface module ...... 29 ISO/OSI reference model ...... 2 Cell level ...... 1 Issue of a certificate...... 28 Certification...... 28 Clock synchronization...... 11 K Comm-FB ...... 24 Communication Keys to success...... 6 Communication in automation...... 1 Communications protocols...... 10 L Competence Centers...... 33 Links...... 9 conformity test ...... 28 CPF...... 3 M Cyclic data communication...... 13 Manufacturer ID ...... 26 MBP ...... 8 D Modular devices...... 21 Data Data frame...... 2 O Lateral data communication...... 11 OPC ...... 32 Device management...... 25 Device types ...... 11 P Diagnostic functions ...... 12 PA devices...... 20 Documentation ...... 33 Physical Block (PB) ...... 20 DP...... 6 PROFIBUS...... 4 DP-V0...... 11 PROFIBUS DP ...... 10 DP-V1...... 11 PROFIBUS International ...... 4 DP-V2...... 11 PROFIBUS User Organization ...... 33 DPM PROFIdrive ...... 19 DPM1 ...... 11, 12 Profiles ...... 2, 6 DPM2 ...... 12 Profile ID...... 26 DTM...... 25 PROFInet...... 3, 31 E The PROFInet engineering model...... 31 PROFIsafe ...... 17 EDD ...... 25, 26 Protocol chips ...... 29 F R FDT/DTM concept ...... 27 Remote I/Os...... 22 Fiber optics ...... 9 Repeaters ...... 7 Field level...... 1 RPA...... 33 FISCO model...... 10 RS485 Fluid power ...... 21 RS485...... 5 FMS ...... 5 RS485-IS ...... 5, 7 G S General application profiles...... 17 Segment couplers...... 9 GSD...... 25 SEMI ...... 22 SIL monitor...... 17

PROFIBUS Technology and Application, October 2002 35

Slaves Transmission technology ...... 7 Slave redundancy ...... 18 Slaves...... 12 U Slave-to-slave communications ...... 14 Upload and download ...... 14 Software components...... 27 User benefits...... 1 Specific application profiles ...... 19 Sync and freeze mode...... 13 V System Version System behavior ...... 12 Version DP-V1...... 14 System profiles...... 23 Version DP-V2...... 14 T X Time stamps ...... 18 XML...... 32 Transducer Block (TB)...... 20

36 PROFIBUS Technology and Application, October 2002

PROFIBUS System Description Version October 2002

Order Number 4.002

Publisher PROFIBUS Nutzerorganisation e.V. PNO PROFIBUS Trade Organization PTO Haid-und-Neu-Str. 7 16101 N. 82nd Street, Suite 3B 76313 Karlsruhe AZ 85260 Scottsdale Deutschland USA Tel.: ++49 (0) 721 / 96 58 590 Tel.: ++1 480 483 2456 Fax: ++49 (0) 721 / 96 58 589 Fax: ++1 480 483 7202 [email protected] [email protected]

Liability Exclusion

PNO / PTO has elaborated the contents of this brochure carefully. Nevertheless, errors can not be excluded. Liability of PNO / PTO is excluded, regardless of its reason. The data in this brochure is checked periodically, however. Necessary corrections will be contained in subsequent versions. We gratefully accept suggestions for improvement.

Terms used in this brochure may be trade marks, their use by third parties for any purposes may vio- late the rights of the owner.

This brochure is not a substitute for standards IEC 61158 and IEC 61784 and the PROFIBUS guidelines and profiles. In case of doubt, IEC 61158 and IEC 61784 take precedence.

02092 PNO Titel AR1 07.08.2002 11:15 Uhr Seite 3

Australia and New Zealand PROFIBUS Nutzerorganisation PROFIBUS Slovakia PROFIBUS User Group (ANZPA) Haid-und-Neu-Straße 7 c/o Dept. of Automation KAR FEI STU c/o OSItech Pty. Ltd. 76131 Karlsruhe Slovak Technical University P.O. Box 315 Phone ++49 7 21 96 58 590 Ilkovièova 3 Kilsyth, Vic. 3137 Fax ++49 7 21 96 58 589 812 19 Bratislava Phone ++61 3 9761 5599 [email protected] Phone ++421 2 6029 1411 Fax ++61 3 9761 5525 Fax ++421 2 6542 9051 [email protected] Irish PROFIBUS User Group [email protected] c/o Flomeaco Endress + Hauser PROFIBUS Belgium Clane Business Park PROFIBUS Association South East Asia August Reyerslaan 80 Kilcock Road, Clane, Co. Kildare c/o Endress + Hauser 1030 Brussels Phone ++353 45 868615 1 Int. Bus. Park #01-11/12 The Synergy Phone ++32 2 706 80 00 Fax ++353 45 868182 609917 Singapore Fax ++32 2 706 80 09 [email protected] Phone ++65 566 1332 [email protected] Fax ++65 565 0789 PROFIBUS Network Italia [email protected] Association PROFIBUS Brazil Via Branze, 38 c/o Siemens Ltda IND1 AS 25123 Brescia (I) PROFIBUS User Organisation Southern Africa R. Cel. Bento Bicudo, 111 Phone ++39 031 3384030 P.O. Box 26 260 05069-900 Sao Paolo, SP Fax ++39 030 396999 East Rand Phone ++55 11 3833 4958 [email protected] Phone ++27 11 397 2900 Fax ++55 11 3833 4183 Fax ++27 11 397 4428 [email protected] Japanese PROFIBUS Organisation [email protected] TFT building West 9F Chinese PROFIBUS User Organisation 3-1 Ariake Koto-ku PROFIBUS i Sverige c/o China Ass. for Mechatronics Technology Tokyo 135-8072 Kommandörsgatan 3 and Applications Phone ++81 3 3570 3034 28135 Hässleholm 1Jiaochangkou Street Deshengmenwai Fax ++81 3 3570 3064 Phone ++46 4 51 49 460 100011 Bejing [email protected] Fax ++46 4 51 89 833 Phone ++86 10 62 02 92 18 [email protected] Fax ++86 10 62 01 78 73 Korea PROFIBUS Association [email protected] #306, Seoungduk Bldg. PROFIBUS Nutzerorganisation Schweiz 1606-3, Seocho-dong, Seocho-gu Kreuzfeldweg 9 PROFIBUS Association Czech Republic Seoul 137-070, Korea 4562 Biberist Karlovo nam. 13 Phone ++82 2 523 5143 Phone ++41 32 672 03 25 12135 Prague 2 Fax ++82 2 523 5149 Fax ++41 32 672 03 26 Phone ++420 2 2435 76 10 [email protected] [email protected] Fax ++420 2 2435 76 10 [email protected] PROFIBUS Nederland The PROFIBUS Group U.K. c/o FHI Unit 6 Oleander Close PROFIBUS Denmark P.O. Box 2099 Locks Heath, Southampton, Hants, SO31 6WG Maaloev Byvej 19-23 3800 CB Amersfoort Phone ++44 1489 589574 2760 Maaloev Phone ++31 33 469 0507 Fax ++44 1489 589574 Phone ++45 40 78 96 36 Fax ++31 33 461 6638 [email protected] Fax ++45 44 65 96 36 [email protected] [email protected] PROFIBUS Trade Organization, PTO PROFIBUS User Organisation Norway 16101 N. 82nd Street, Suite 3B PROFIBUS Finland c/o AD Elektronikk AS Scottsdale, AZ 85260 USA c/o AEL Automaatio Haugenveien 2 Phone ++1 480 483 2456 Kaarnatie 4 1401 Ski Fax ++1 480 483 7202 00410 Helsinki Phone ++47 909 88640 [email protected] Phone ++35 8 9 5307259 Fax ++47 904 05509 Fax ++35 8 9 5307360 [email protected] [email protected] PROFIBUS User Organisation Russia France PROFIBUS c/o Vera + Association 4, rue des Colonels Renard Nikitinskaya str, 3 75017 Paris 105037 Moscow, Russia Phone ++33 1 45 74 63 22 Phone ++7 0 95 742 68 28 Fax ++33 1 45 74 03 33 Fax ++7 0 95 742 68 29 [email protected] [email protected]

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