Ethercat Brochure

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The Ethernet Fieldbus ETG_Broschuere_09_2009_RZ.qxd 02.10.2009 14:30 Uhr Seite 2

■ Content

2 EtherCAT Technology Group

03 Why EtherCAT?

4 User and Vendor Statements

6 EtherCAT Technology Group

8 EtherCAT – Technical Introduction and Overview

18 Implementation Aspects | Master |Slave

22 Conformance and Interoperability

24 Safety over EtherCAT

26 Why do companies choose EtherCAT?

28 Contact

■ Why EtherCAT? EtherCAT Technology Group 3

■ It’s faster ■ It’s versatile | The fastest system available, | master-slave, slave-slave and with outstanding synchronization features master-master communication | Performance widely independent of topology | Cyclic and acyclic services for process data | No underlying sub-system required any more and parameter data | Meets today’s and tomorrow’s requirements | Suitable for centralized and distributed control architectures ■ It’s cost effective | Machine control, robotics, embedded systems, | Meets or even undercuts fieldbus cost levels building automation, transport systems, … | No special master cards required – on-board MAC or low cost standard NIC is fine ■ It’s Industrial Ethernet | Highly integrated Slave Controllers for | Standard Ethernet frames used lower interface costs | Supports all Internet technologies | No active infrastructure components required | HTTP, FTP,TCP/IP – without degrading the real-time behavior ■ It’s easy to implement | Simplifies vertical integration | Real-time protocol handling in hardware | Device application determines μC performance – ■ It’s Safety on Ethernet not the fieldbus protocol | Functional Safety and standard application | Simple I/O slaves do not require μC at all with one network | Universal slave interface modules available | Safety Protocol according to international | Evaluation kits and stacks for master safety standard IEC 61508 and slave available | Suitable for safety I/O and safety drives | Routable via gateways and fieldbus systems ■ It’s easy to use | No manual address setting ■ It’s open | No switch or router configuration | Open Technology, fully disclosed | Auto configuration features | Supported by the worlds largest Industrial | Diagnosis with exact localization Ethernet Organization | EtherCAT is IEC, ISO and SEMI standard ■ It’s flexible topology | Supports well established device profiles | All topologies supported: line, tree, star, ring | No node, switch or hub cascading issues ■ It’s well proven | Up to 65,535 nodes per segment | Deployed in series applications since 2003 | Redundancy, Hot Connect, Hot Swap options | Wide range of applications | Implemented on variety of controllers and operating systems | Large product selection

■ User and Vendor Statements

4 EtherCAT Technology Group

■ Martin Rostan, Head of Technology ■ Dieter Hess, Managing Marketing, Beckhoff Automation GmbH, Director, 3S Smart Software and Executive Director, Solutions GmbH: EtherCAT Technology Group: “3S decided to implement EtherCAT as “The strong growth of the EtherCAT Technology Group the first real-time Ethernet protocol, reflects the tremendous worldwide interest in this since EtherCAT utilizes the maximum exiting technology. Manufacturers and end users rec- performance of Ethernet. For us as a ognize the benefits: future-proof performance, flexible network topology, simple software manufacturer, the fact that the master implementation configuration, and low costs. Nevertheless, while the number of members is an is independent of special plug-in cards is particularly attractive. important criterion for the success of a technology organization, it is not the cru- The software can be based on the universally available standard cial one. Acceptance of the technology resulting in product developments and ap- Ethernet controller. The openness of the system and active sup- plications is even more important. Here too, EtherCAT is setting standards.” port of Beckhoff for ETG are further significant factors.”

■ Erich Hutflesz, Manager Control Systems, ■ Kenichi Karigane, Schuler SMG, and ETG Board Member: General Manager, “EtherCAT enables us to realize fast drive and hydrau- Drive Systems Division, lic controls for all applications currently used in the Product Marketing & Sales Schuler Group. Another crucial factor is that, due to Engineering Center, EtherCAT’s performance, we still have enough poten- Hitachi IES Co., Ltd.: tial for solving complex control tasks in future without EtherCAT is being adopted also in speed problems. Apart from the functional features of a technology, availability Japan: major industrial machinery manufacturers are introducing of a wide range of components is very significant for users of automation devices. EtherCAT into their machines. With more EtherCAT based ma- The fact that so shortly after ETG was established so many member companies chines made available on the market the potential of EtherCAT ap- were already presenting EtherCAT products and that further products are in plications will even further increase. We at Hitachi IES were quick preparation is clear evidence for the success of this technology. The main factor off the mark in releasing our large capacity AC servo system with determining user acceptance continues to be simple and effective handling of EtherCAT and will further enhance our line-up of EtherCAT prod- the EtherCAT system in terms of configuration and diagnosis.” ucts since EtherCAT has superiority of quality to other motion control bus systems with regards to speed, cost performance and openness.

■ Dr. Peter Heidrich, R&D Manager, ■ Shinya Yamasaki, Baumüller GmbH, and ETG Board Member: Senior General Manager, Control “Baumüller decided to use EtherCAT due to the signif- Devices Division HQ, Omron: icant benefits it can offer, particularly in terms of “Omron has selected EtherCAT as price/performance ratio and availability. This decision Machine control network dedicated was underlined through our active collaboration in mainly for its new motion & field de- the ETG executive committee. We continue to be con- vices bus system since it provides a vinced that the decision for EtherCAT was the right one. As soon as EtherCAT Slave unique combination of performance, ease of use and topology Controllers became available, Baumüller started producing connections for the freedom. Omron believes in open architectures, and has therefore also decided to support and promote EtherCAT in Japan and in the bmaXX 4400 system in August 2004. ETG has demonstrated that, due to the uni- Asian Market. Our first EtherCAT products are motion controller versality of the EtherCAT technology, EtherCAT-based systems can be developed and PLC master units together with servo motors, inverters, vision and realized very quickly.” sensors and field I/Os.”

EtherCAT Technology Group 5

■ Hans Beckhoff, ■ Norbert Hauser, Managing Director, VP Marketing, Beckhoff Automation GmbH: Kontron AG: “Naturally, EtherCAT is particularly suitable “EtherCAT is currently the most successful for fast PC-based controls. The master re- Ethernet-based fieldbus. This is also visible in quires no plug-in card and can be imple- the strongly growing number of members of mented on any existing Ethernet controller renowned companies. A major advantage of using a very simple interface. EtherCAT is therefore also well suited to EtherCAT is its openness, high performance and the excellent price-per- small and medium control technology, where it opens up new areas of formance ratio. Kontron‘s embedded computing customers have identi- application for distributed control. Therefore EtherCAT is the commu- fied the advantages of EtherCAT for their business. Therefore, Kontron, nication backbone of Beckhoff system architecture and we are very one of the leading companies in the Embedded Computing market, has pleased about the worldwide success of this technology.” decided to offer the embedded portfolio also with EtherCAT.”

■ Thomas Porath, ■ Chris Choi, System Architect General X-Ray, Director of Technology, Husky Philips Medical Systems: Injection Molding Systems Ltd.: “We believe that EtherCAT is the right “The design of EtherCAT assures its cost effec- technology for the next step towards a sys- tiveness by the use of long-lasting low cost PC tem control architecture that enables us to and Ethernet components. This steers engi- further reduce costs and allows for new in- neering and investment decisions towards its novations, which the current architecture is not suitable to serve for. The intensive use. In injection molding, a control cycle in the range of mS is an performance of EtherCAT will allow us to implement hard real-time, safe- industrial norm. EtherCAT has proven itself as the most effective industri- ty, and control-functions on one single cable, while simultaneously offer- al Ethernet protocol to achieve high performance control for injection ing flexible topologies, which will reduce cable-costs significantly. molding with a control cycle down to the 100 μS range. This has resulted Not only performance, but also international standardization and world- in an improved reaction time which brings great benefits: enabling offer wide acceptance are important features of EtherCAT. Our changeover to of products with productivity surpassed the status quo; and producing EtherCAT is simplified through the use of CANopen device profiles and the molded parts at higher precision and better quality.We are confident that availability of gateways and converters, since we are not able to convert EtherCAT is a right technology to support our product innovation.” all of our subsystems and components in one big step.”

■ Pat Boland, Managing Director, ■ Dmitry Dzilno, Director of Engineering, ANCA Pty Ltd.: Controls Group, Applied Materials Inc.: “ANCA’s interest in EtherCAT as the stan- “We implemented EtherCAT in a few applica- dard fieldbus in our CNC machines has tions and find especially exciting that this pro- been driven by three main features. Firstly tocol allows us to have very high update rates there is the practically unlimited band- which allows extremely cost efficient close loop width offered by EtherCAT which gives our control to be implemented by SW means with designers freedom to imagine, scalability and long product lifetime. Sec- virtually no specialized HW added. Availability of EtherCAT enabled field- ondly the two physical layers give the option of choosing low cost, elec- bus scanners, digital motion amplifiers as well as fast I/O allows for using trically rugged and widely available hardware components. Finally the slim controller PC with just one Ethernet port instead of multiple PC slots. software only master allows easy use of high reliability, relatively low cost Introducing EtherCAT hence does not require abandoning all well estab- industrial motherboards as system controllers.” lished fieldbus systems right away but provides a smooth migration path.”

■ EtherCAT Technology Group

ETG-Team

6 EtherCAT Technology Group

Everyone should be able to use and implement EtherCAT. product guides, issue press releases and articles, promote The EtherCAT Technology Group stands for this philosophy. EtherCAT via its website and organize joint fair and exhibi- The ETG is a forum for end users from different sectors, and tion booths. for machine manufacturers and suppliers of powerful control technology with the aim of supporting and promoting Benefits of membership EtherCAT technology. The wide range of industry sectors ■ EtherCAT device vendors are encouraged to join ETG so that are represented ensures that EtherCAT is optimally that they get access to development products and imple- prepared for a large number of applications. With their mentation support as well as their own EtherCAT vendor qualified feedback, the system partners ensure simple in- ID and the Conformance Test Tool. EtherCAT users support tegration of the hardware and software components in all the technology and its adaptation to their industry by required device classes. joining the ETG. The ETG Technical Committee meets frequently to re- ■ Members are eligible to participate in working groups view the technology. Working Groups look after topics like and thus influence on future enhancements of the device profile integration, safety,wiring, standardization or EtherCAT technology specifications. conformance and certification. ■ ETG represent the member’s interest in international In Training Classes and Seminars the ETG provides de- standardization committees such as IEC and ISO. tailed information about the technology. Plug Fests help to ■ ETG members have access to the members-only part of provide interoperability and implementation support and the EtherCAT website, which provides specifications, a de- complement the conformance test and certification velopers forum, the EtherCAT Knowledge Base and other process. The ETG Offices answer technical inquiries re- up-to-date information regarding the technology. garding EtherCAT, provide marketing assistance, publish

EtherCAT Technology Group 7

The Management Board of the International Electrotech- Also SEMI (Semiconductor Equipment and Materials nical Commission (IEC) approved the Liaison of the International) has approved EtherCAT for their applications EtherCAT Technology Group with the IEC Committees for by accepting the EtherCAT SEMI standard E54.20. The lead- Digital Communication: The ETG is official standardization ing standards organizations thus respond to the growing partner organization. interest of the industry in the fastest Industrial Ethernet solution. International Standardization The EtherCAT specification is an international IEC and ISO Membership Development standard: EtherCAT is part of the international fieldbus Founded in 2003, the EtherCAT Technology Group grew so standard IEC 61158 (Digital data communication for meas- fast that it became the worlds largest Industrial Ethernet urement and control – Fieldbus for use in industrial con- organization. With over 1000 member companies from all trol systems). In part 2 of IEC 61784 profiles for specific over the world and still growing, the ETG is a strong inter- EtherCAT device classes are defined. The new part 3 of this national community. ETG Offices in Europe, Asia and North standard includes the Safety over EtherCAT specification, America provide support and members services. The cur- and the new edition of part 5 covers the EtherCAT network rent membership list can be found on the EtherCAT web- installation. ISO 15745 deals with device description as- site. pects. The IEC 61800-7 is particularly important for Motion How to join the ETG Control applications. The integration of EtherCAT in this ETG headquarters provides all necessary information in- standard makes it a standardized communication technol- cluding ETG by-laws and application form on request: ogy for the SERCOS™ and CANopen™ drive profiles. info@ethercat.org

■ Technical Introduction and Overview

8 EtherCAT Technology Group

This section provides an in-depth introduction into EtherCAT, the Ethernet-based fieldbus system. EtherCAT sets new performance standards. Handling is straightforward and similar to a fieldbus, thanks to flexible topology and simple configuration. Moreover, since EtherCAT can be implemented very cost-effectively, the system enables fieldbuses to be used in applications where fieldbus networking was not an option in the past.

■ Introduction fieldbus systems in the past. The main requirements for Fieldbuses have become an integrated component of au- this type of application are high real-time capability, suit- tomation technology.They have been tried and tested and ability for small data quantities, and naturally cost-effec- are now widely established. It was fieldbus technology tiveness. EtherCAT meets these requirements and at the that enabled the wide-scale application of PC-based con- same time makes internet technologies available at the trol systems. While the performance of controller CPUs – I/O level. particularly for IPCs – is increasing rapidly, conventional With EtherCAT the controller can update the input fieldbus systems tend to represent “bottlenecks” that lim- and/or output information at the time when the data is it the performance control systems can achieve. An addi- needed. The I/O response time contains all hardware rele- tional factor is the layered control architecture consisting vant delays (IPC, EtherCAT and I/O system) from the physi- of several subordinate (usually cyclic) systems: the actual cal input signal to the physical reaction on the output. control task, the fieldbus system and perhaps local expan- With response times down to below 100 μs this offers a sion buses within the I/O system or simply the local performance to the PLC level that has been available up to firmware cycle in the peripheral device. Reaction times are now only within servo drives with a digital signal proces- typically 3–5 times higher than the controller cycle time – sor (DSP), (see Fig. 1). an unsatisfactory solution. Above the fieldbus system level, i.e. for networking ■ Ethernet and real-time capability controllers, Ethernet has already been the state of the art There are many different approaches that try and provide for some time. What is relatively new is its application at real-time capability for Ethernet: for example, the CS- the drive or I/O level, i.e. in areas that were dominated by MA/CD media access procedure is disabled via higher level

■ Figure 1: Ultra short cycle times with I/O response time < 100 μs ■ Figure 2: Comparison of Bandwidth Utilisation

80-97% 100 90 80 70 60 50 40 20-30% 30 20 10 2-5% 0 Polling/ Broadcast EtherCAT Timeslicing Master➝Slave

At 4 Byte user data From 2 Bit per note user data per note

EtherCAT Technology Group 9

protocol layers and replaced by the time slice procedure or passes through the node. Similarly, input data is inserted polling; other propositions use special switches that dis- while the telegram passes through (see Fig. 3). The frames tribute Ethernet packets in a precisely controlled timely are only delayed by a few nanoseconds. The frame send by manner. Whilst these solutions may be able to transport the master is passed through to the next device until it data packets more or less quickly and accurately to the reaches the end of the segment (or branch).The last device connected Ethernet nodes, the times required for the redi- detects an open port and therefore sends the frame back rection to the outputs or drive controllers and for reading to the master. the input data strongly depend on the implementation. On the other hand, an EtherCAT frame comprises the If individual Ethernet frames are used for each device, data of many devices both in send and receive direction the usable data rate is very low in principle: The shortest within one Ethernet frame. The usable data rate increases Ethernet frame is 84 bytes long (incl. inter-packet gap IPG). to over 90%. The full-duplex features of 100BASE-TX are If, for example, a drive cyclically sends 4 bytes of actual val- fully utilized, so that effective data rates of >100 Mb/s ue and status information and accordingly receives 4 bytes (>90% of 2 x 100 Mb/s) can be achieved (see Fig. 2). of command value and control word information, at 100% The EtherCAT master uses standard Ethernet Medium bus load (i.e. with infinitely short response time of the Access Controllers (MACs) without extra communication drive) a usable data rate of only 4/84 = 4.8% is achieved. At processors. Thus an EtherCAT master can be implemented an average response time of 10 μs, the rate drops to 1.9%. on any equipment controller that provides an Ethernet in- These limitations apply to all real-time Ethernet approach- terface, independently of the operating system or applica- es that send an Ethernet frame to each device (or expect a tion environment. frame from each device), irrespective of the protocols used The EtherCAT slave uses an EtherCAT Slave Controller within the Ethernet frame. (ESC) for processing the data “on-the-fly”. Thus the performance of the network is not determined by the micro- ■ EtherCAT operating principle controller performance of the slave but is handled com- EtherCAT technology overcomes these inherent limitations plete in hardware. A process data interface (PDI) to the of other Ethernet solutions: On the one hand the Ethernet slave‘s application offers a Dual-Port-RAM for data ex- packet is no longer received then interpreted and process change. data then copied at every device, but the EtherCAT slave devices read the data addressed to them while the frame

■ Figure 3: Process data is inserted in datagram

Ethernet Header ECAT HDR Datagram 1 Datagram 2 Datagram 3 Ethernet

Logical Process Image Logical Process Image Logical Process Image Task 1 Task 2 Task 3

10 EtherCAT Technology Group

■ Protocol systems. Even communication across routers into other EtherCAT only uses standard frames according to IEEE subnets is possible. In this variant, system performance ob- 802.3 – the frames are not shortened. EtherCAT frames can viously depends on the real-time characteristics of the con- thus be sent from any Ethernet controller (master), and trol and its Ethernet protocol implementation. The re- standard tools (e.g. monitor) can be used. sponse times of the EtherCAT network itself are hardly re- The EtherCAT device protocol is optimized for process stricted at all: once inside an EtherCAT segment the UDP data and is transported directly within the Ethernet frame protocol does not have to be processed any more. thanks to a special EtherType. It may consist of several To access the local memory of the devices for example EtherCAT datagrams, each serving a particular memory for configuration either the position of the devices in the area within the 4 gigabyte address space. For small I/O de- segment can be addressed or the device is addressed via an vices the EtherCAT Slave Controller also supports bitwise assigned node address.This means: No manual address ad- mapping. The bits of an input device can be inserted indi- justment on the devices is needed! vidually anywhere within the logical address space. If an The position addressing is used for the boot-up of the EtherCAT datagram is sent that reads a certain process im- network. The master can identify each device in the seg- age area the input terminal inserts its data at the right ment (Vendor-ID, product code, etc.) and can read in the place within the data area. This is done by the Fieldbus link status of the device‘s ports.Therefore the complete in- Memory Management Unit (FMMU) within the ESC. So the formation about all devices and about the topology is data sequence becomes independent of the physical order available and can be compared to an expected configura- of the Ethernet terminals in the network; addressing can tion. Additionally, the master assigns the node address to be in any order. Broadcast, Multicast and communication all devices. between slaves are possible. Direct Ethernet frame trans- This node address is used afterwards and addresses the fer is used in cases where maximum performance is re- devices reliably even if one or more devices are not con- quired and the EtherCAT components are operated in the nected (e.g. Hot Connect groups) and therefore the posi- same subnet as the controller. tion in the segment is not the same. However, EtherCAT applications are not limited to a In addition to the EtherCAT device protocol using data single subnet: EtherCAT UDP packages the EtherCAT proto- exchange according to the master/slave principle, the col into UDP/IP datagrams (see Fig. 4). This enables any EtherCAT automation protocol makes it also very suitable control with Ethernet protocol stack to address EtherCAT for communication between controllers (e.g. master/mas-

■ Figure 4: EtherCAT: Standard Frames according to IEEE 802.3 [3]

Ethernet Header ECAT EtherCAT Telegram Ethernet DA SA Type Frame HDR Datagram 1 Datagram 2 -- Datagram n Pad. FCS

(6) (6) (2/4) (2) (10+n+2) (10+m+2) (10+k+2) (0…32) (4) Ethertype 88A4h

Ethernet IP Header UDP Header ECAT HDR EtherCAT Telegram Ethernet Header Ethertype 0800h (20) (8) UDP-Port: 88A4h

EtherCAT Technology Group 11

ter). Pushed and polled process data exchange and a vari- Wiring flexibility is further maximized through the ety of services for parameterization, diagnosis and remote choice of different cables. Flexible and inexpensive stan- control cover a wide range of requirements.The data inter- dard Ethernet cables transfer the signals in 100BASE-TX faces of the device protocol and the automation protocol mode. The Power over EtherCAT-option (compatible with are identical. IEEE 802.3af) allows one to connect e.g. sensors using a sin- For slave-to-slave communication, two mechanisms gle cable. Fibre Optics (100BASE-FX or Plastic Optical Fibres) are available. Upstream devices can communicate to complement the system for special applications. The com- downstream devices within the same cycle – and thus ex- plete choice of Ethernet wiring – such as different optical tremely fast. Since this method is topology-dependent, it is fibers and copper cables – can be used in combination with particularly suitable for slave-to-slave communication re- switches or media converters. lationships given by machine design – e.g. in printing or The Fast Ethernet physics (100BASE-TX) enables a cable packaging applications. For freely configurable slave-to- length of 100 m between two devices. Since up to 65,535 slave communication, the second mechanism applies: the devices can be connected, the size of the network is almost data is relayed by the master. Here, two cycles are needed, unlimited. but due to the extraordinary performance of EtherCAT this The Ethernet protocol according to IEEE 802.3 remains is still faster than any other approach. intact right up to the individual device; no sub-bus is required. In order to meet the requirements of a modular de- ■ Topology vice like an electronic terminal block, the physical layer in Line, tree or star: EtherCAT supports almost any topology the coupling device can be converted from twisted pair or (see Fig. 5). The bus or line structure known from the field- optical fiber to LVDS (alternative Ethernet physical layer, buses thus also becomes available for Ethernet, without standardized in [4,5]). A modular device can thus be ex- the quantity limitations implied by cascaded switches or tended very cost-efficiently. Subsequent conversion from hubs. the backplane physical layer LVDS to the 100BASE-TX phys- Particularly useful for system wiring is the combina- ical layer is possible at any time – as usual with Ethernet. tion of line and branches or stubs: the required interfaces exist on many devices (e.g. on I/O modules); no additional switches are required. Naturally, the classic Ethernet star topology can also be used.

■ Figure 5: Flexible Topology: Line, Tree or Star

12 EtherCAT Technology Group

■ Distributed clocks would lead to large step changes in the computed velocity. Accurate synchronization is particularly important in cases Since by using the distributed clocks the sampling is not where spatially distributed processes require simultane- based on the communication jitter, very precise velocity ous actions. This may be the case, for example, in applica- measurements are achieved. It is orders of magnitude bet- tions where several servo axes carry out coordinated move- ter than that of measuring techniques based on jitter-free ments simultaneously. communication. However, high-resolution distributed The most powerful approach for synchronization is the clocks are not only used for synchronization, but can also accurate alignment of distributed clocks, as described for provide accurate information about the local timing of the example in the IEEE 1588 standard [6]. In contrast to fully data acquisition. With EtherCAT, timestamp data types are synchronous communication, where synchronization qual- introduced as a logical extension. The high resolution sys- ity suffers immediately in the event of a communication tem time is linked to the measured value, which is made fault, distributed aligned clocks have a high degree of tol- possible by the large bandwidth offered by Ethernet. This erance versus possible fault-related delays within the com- feature is not only very useful for any measurement appli- munication system. cation, but also enables very precise reaction times inde- With EtherCAT, the synchronization of the devices is pendent of the control cycle. External synchronization, e.g. fully based on a pure hardware machine. Since the com- across the plant, is then based on IEEE 1588. munication utilizes a logical (and thanks to full-duplex Fast Ethernet also physical) ring structure, a timestamp can be ■ Performance sampled within each device for the incoming and the re- EtherCAT reaches new dimensions in network perform- turning frame. With these timestamps the master can de- ance. Thanks to hardware integration in the slave and di- termine the propagation delay offset to the individual rect memory access to the network controller in the mas- slave clocks simply and accurately (see Fig. 7). The distrib- ter, the complete protocol processing takes place within uted clocks are adjusted based on this value, which means hardware and is thus fully independent of the run-time of that a very precise network-wide time base with a jitter of protocol stacks, CPU performance or software implemen- significantly less then 1 microsecond is available (see tation. The update time for 1,000 I/Os is only 30 μs – in- Fig. 6).This is very important e.g. for motion control, where cluding I/O cycle time (see Table 1). Up to 1486 bytes of typically velocities are calculated from sequentially meas- process data can be exchanged with a single Ethernet ured positions. Particularly with very short sampling times, frame – this is equivalent to almost 12,000 digital inputs even a small temporal jitter in the position measurement and outputs. The transfer of this data quantity only takes

■ Figure 6: Synchronicity and Simultaneousness: Scope view of two ■ Figure 7: Setting the individual clocks of each device to the network-wide time base. distributed devices with 300 nodes and 120m of cable between them M s Δt

s s s s s s

EtherCAT Technology Group 13

150 μs. The communication with 100 servo axes is also ex- consistency with the specified configuration. The topology tremely fast: every 100μs, all axes are provided with com- should also match the configuration. Due to the built-in mand values and control data and report their actual posi- topology recognition down to the individual terminals, tion and status. The distributed clock technique enables this verification can not only take place during system the axes to be synchronized with a deviation of signifi- start-up, automatic reading in of the network is also possi- cantly less than 1 microsecond. And even at this pace, there ble (configuration up-load). is more than sufficient bandwidth for asynchronous com- Bit faults during the transfer are reliably detected munications such as TCP/IP, parameter download or diag- through evaluation of the CRC checksum: The 32 bit CRC nostic data upload. polynomial has a minimum hamming distance of 4. Apart The extremely high performance of the EtherCAT tech- from broken wire detection and localization, the protocol, nology enables control concepts that could not be realized physical layer and topology of the EtherCAT system enable with classic fieldbus systems. With EtherCAT, a communi- individual quality monitoring of each individual transmis- cation technology is available that matches the superior sion segment. The automatic evaluation of the associated computing capacity of modern Industrial PCs. The bus sys- error counters enables precise localization of critical net- tem is no longer the bottleneck of the control concept. Dis- work sections. Gradual or changing sources of error such as tributed I/Os are recorded faster than is possible with most EMI influences, defective connectors or cable damage are local I/O interfaces. The EtherCAT technology principle is detected and located, even if they do not yet overstrain the scalable and not bound to the baud rate of 100 Mbaud – self healing capacity of the network. extension to Gbit Ethernet is possible. ■ High availability ■ Diagnosis Increasing demands in terms of system availability are Experience with fieldbus systems shows that availability catered for with optional cable redundancy that enables and commissioning times crucially depend on the diag- devices to be exchanged without having to shut down the nostic capability. Only faults that are detected quickly and network. Adding redundancy is very inexpensive: the only accurately and located unambiguously can be rectified additional hardware is another standard Ethernet port (no quickly.Therefore, special attention was paid to exemplary special card or interface) in the master device and the sin- diagnostic features during the development of EtherCAT. gle cable that turns the line topology into the ring (see During commissioning, the actual configuration of the Fig. 8). Switchover in case of device or cable failure only nodes (e.g. drives or I/O terminals) should be checked for takes one cycle, so even demanding motion control appli-

■ Table 1: EtherCAT Performance Overview ■ Figure 8: Low cost cable redundancy with standard slaves

Process Data Update Time 256 distributed digital I/O 11 μs = 0,01 ms 1000 distributed digital I/O 30 μs 200 analog I/O (16 bit) 50μs ↔ 20 kHz 100 Servo Axis, with 8 Bytes 100 μs input and output data each 1 Fieldbus Master-Gateway 150 μs (1486 Bytes Input and 1486 Bytes Output Data)

14 EtherCAT Technology Group

cations survive a cable failure without problems. EtherCAT ■ EtherCAT instead of PCI also supports redundant masters with hot standby func- With increasing miniaturization of the PC components, the tionality. Since the EtherCAT Slave Controllers immediately physical size of Industrial PCs is increasingly determined by return the frame automatically if an interruption is en- the number of required slots. The bandwidth of Fast Ether- countered, failure of a device does not necessarily lead to net, together with the process data width of the EtherCAT the complete network being shut down. Drag chain appli- communication hardware enables new directions: classic cations, for example, can thus be specifically configured as interfaces that are conventionally located in the IPC are stubs in order to be prepared for cable break or use cable transferred to intelligent EtherCAT interface terminals (see redundancy right away. Fig. 9). Apart from the decentralized I/Os, drives and control units, complex systems such as fieldbus masters, fast ■ Safety serial interfaces, gateways and other communication in- Conventionally, safety functions are realized separately terfaces can be addressed. from the automation network, either via hardware or us- Even further Ethernet devices without restriction on ing dedicated safety bus systems. Safety over EtherCAT en- protocol variants can be connected via decentralized ables safety-related communication and control communi- switchport devices. The central IPC becomes smaller and cation on the same network. The safety protocol is based therefore more cost-effective. One Ethernet interface is on the application layer of EtherCAT, without influencing sufficient for the complete communication with the pe- the lower layers. It is certified according to IEC 61508 and riphery (see Fig. 10). meets the requirements of Safety Integrity Level (SIL) 3.The data length is variable, making the protocol equally suit- ■ Device profiles able for safe I/O data and for safe drive technology. There The device profiles describe the application parameters are no restrictions regarding the communication medium and the functional behavior of the devices including the or the transfer rate. Like other EtherCAT data, the safety da- device class-specific state machines. For many device class- ta can be routed without requiring safety routers or gate- es, fieldbus technology already offers reliable device pro- ways. First fully certified products featuring Safety over files, for example for I/O devices, drives or valves. Users are EtherCAT are available since 2005. ETG also developed a familiar with these profiles and the associated parameters Safety Drive Profile which provides a uniform data inter- and tools. No EtherCAT-specific device profiles have there- face to the safety functionalities of drives and thus simpli- fore been developed for these device classes. Instead, sim- fies the setup and configuration. ple interfaces for existing device profiles are being offered

■ Figure 9: Decentralized Fieldbus Interfaces

EtherCAT Technology Group 15

(see Fig. 11). This greatly assists users and device manufac- to EtherCAT (SoE) is specified in part 304 [8]. The service turers alike during the migration from the existing fieldbus channel, and therefore access to all parameters and func- to EtherCAT. At the same time the EtherCAT specification tions residing in the drive, is based on the EtherCAT mail- keeps it simple because all the protocols are optional. The box. Here too, the focus is on compatibility with the exist- device manufacturer only has to implement the protocol ing protocol (access to value, attribute, name, units, etc. of that the device application needs. the IDNs) and expandability with regard to data length limitation.The process data, with SERCOS in the form of AT ■ CAN application protocol over EtherCAT (CoE) and MDT data, are transferred using EtherCAT device pro- CANopen™ device and application profiles are available for tocol mechanisms. The mapping is similar to the SERCOS a wide range of device classes and applications, ranging mapping. The EtherCAT slave state machine can also from I/O components, drives, encoders, proportional valves be mapped easily to the phases of the SERCOS protocol. and hydraulic controllers to application profiles for plastic EtherCAT provides advanced real-time Ethernet technolo- or textile machinery,for example. EtherCAT can provide the gy for this device profile, which is particularly widespread same communication mechanisms as the familiar in CNC applications. Optionally, the command position, CANopen [7] mechanisms: object dictionary, PDO (process speed or torque can be transferred. Depending on the im- data objects) and SDO (service data objects) – even the net- plementation, it is even possible to continue using the work management is comparable. EtherCAT can thus be same configuration tools for the drives. implemented with minimum effort on devices equipped with CANopen. Large parts of the CANopen firmware can ■ Ethernet over EtherCAT (EoE) be reused. Objects can optionally be expanded in order to The EtherCAT technology is not only fully Ethernet-com- account for the larger bandwidth offered by EtherCAT. patible, but also characterized by particular openness “by design”: the protocol tolerates other Ethernet-based serv- ■ Servo drive profile according to IEC 61800-7-204 ices and protocols on the same physical network – usually (SERCOS) even with minimum loss of performance. There is no re- SERCOS interface™ is acknowledged as a high-perform- striction on the type of Ethernet device that can be con- ance real-time communication interface, particularly for nected within the EtherCAT segment via a switchport. The motion control applications. The SERCOS profile for servo Ethernet frames are tunneled via the EtherCAT protocol, drives and the communication technology are covered by which is the standard approach for internet applications the IEC 61800-7-204 standard. The mapping of this profile (e.g. VPN, PPPoE (DSL), etc.). The EtherCAT network is fully

■ Figure 10: EtherCAT leads to smaller Controllers ■ Figure 11: Several Device Profiles and Protocols can co-exist side by side

File system, HTTP, IEC61800-7-204 CANopen Process Data Bootloader FTP, ... Application Application (SERCOS)

TCP UDP IDN Object Dictionary

File IP Service Channel SDO PDO AT Access Mapping MDT Ethernet

FoE EoE SoE CoE CoE/SoE

Mailbox Process Data EtherCAT Slave Controller

Physical Layer

16 EtherCAT Technology Group

transparent for the Ethernet device, and the real-time ■ Literature characteristics are not impaired (see Fig. 12). [1] EtherCAT Technology Group, http://www.ethercat.org The master acts like a layer 2 switch that redirects the [2] IEC 61158-3/4/5/6-12, Industrial communication frames to the respective devices according to the address networks – Fieldbus specifications – Part 3-12: Data-link layer information. All internet technologies can therefore also service definition – Part 4-12: Data-link layer protocol be used in the EtherCAT environment: integrated web serv- specification – Part 5-12: Application layer service definition – er, e-mail, FTP transfer, etc. Part 6-12: Application layer protocol specification – Type 12 elements (EtherCAT) ■ File Access over EtherCAT (FoE) [3] IEEE 802.3: Carrier Sense Multiple Access with Collision This very simple protocol similar to TFTP enables access to Detection (CSMA/CD) Access Method and Physical Layer any data structure in the device. Standardized firmware Specifications. upload to devices is therefore possible, irrespective of [4] IEEE 802.3ae: CSMA/CD Access Method and Physical whether or not they support TCP/IP. Layer Specifications: Media Access Control (MAC) Parameters, Physical Layers, and Management Parameters for 10GB/s ■ Infrastructure costs Operation. Since no hubs and switches are required for EtherCAT,costs [5] ANSI/TIA/EIA-644-A, Electrical Characteristics of Low associated with these devices including power supply, in- Voltage Differential Signaling (LVDS) Interface Circuits stallation, etc. are avoided. Standard Ethernet cables and [6] IEEE 1588: IEEE Standard for a Precision Clock standard low cost connectors are used, if the environmen- Synchronization Protocol for Networked Measurement tal conditions permit this. For environments requiring in- and Control Systems creased protection sealed connectors according to IEC [7] EN 50325-4: Industrial communications subsystem based on standards are specified. ISO 11898 (CAN) for controller-device interfaces. Part 4: CANopen. [8] IEC 61800-7-301/304, Adjustable speed electrical power drive systems – Part 7-301: Generic interface and use of profiles for power drive systems – Mapping of profile type 1 to network technologies – Part 7-304: Generic interface and use of profiles for power drive systems – Mapping of profile type 4 to network technologies [9] SEMI E54.20:“Standard for Sensor/Actuator Network ■ Figure 12: Transparent for all Ethernet Protocols Communications for EtherCAT”. http://www.semi.org [10] IEC 61784-2, Industrial communication networks – Profiles – Part 2: Additional fieldbus profiles for real-time networks based on ISO/IEC 8802-3 [11] IEC 61784-3 Industrial communication networks – Profiles – Part 3: Functional safety fieldbuses [12] IEC 61784-5 Industrial communication networks –

virtual Ethernet Switch Functionality Profiles – Part 5: Installation of fieldbuses

virtual MAC Address IP Address

EtherCAT Technology Group 17

■ Summary EtherCAT is characterized by outstanding performance, very simple wiring and openness for other protocols. EtherCAT sets new standards where conventional fieldbus systems reach their limits: 1,000 I/Os in 30 μs, optionally twisted pair cable or optical fiber and, thanks to Ethernet and Internet technologies, optimum vertical integration. With EtherCAT, the costly Ethernet star topology can be replaced with a simple line structure – no expensive infrastructure components are required. Where other real-time Ethernet approaches require special interface hardware in the controller, for EtherCAT masters the on-board Ethernet port is sufficient. EtherCAT is versatile: master-to-slave, slave-to- slave and master-to-master communication is supported (see Fig. 13). Safety over EtherCAT is available. EtherCAT makes Ethernet down to the I/O level techni- cally feasible and economically sensible. Full Ethernet compatibility, internet technologies even in very simple devices, maximum utilization of the large bandwidth offered by Ethernet, outstanding real-time characteristics at low costs are outstanding features of this network.

■ Figure 13: Versatile network architecture

■ Implementation Aspects

■ Master 18

The EtherCAT technology was developed with very low cost devices in mind, like I/O terminals, sensors, and embedded controllers. EtherCAT only uses standard Ethernet frames according to IEEE 802.3. These frames are sent by the master device; the slave devices extract and/or insert data on the fly. Thus EtherCAT uses standard Ethernet MACs, where they really make sense: in the master device. And EtherCAT Slave Controllers are used, where such dedicated chips really make sense: in the slave device, where they handle the process data protocol in hardware and provide maximum real-time performance regardless of the local processing power or software quality.

■ EtherCAT Master EtherCAT communicates a maximum of 1,486 bytes of dis- Since EtherCAT uses standard Ethernet frames accord- tributed process data with just one Ethernet frame. Unlike ing to IEEE 802.3, any commercially available Ethernet other solutions where the master device in each network monitoring tool can be used for monitoring EtherCAT com- cycle has to process,send and receive frames for each node, munication. In addition, an EtherCAT parser is part of the EtherCAT systems typically only need one or two frames Wireshark distribution. A Microsoft network monitor plug- per cycle for the entire communication with all nodes. in is also available for processing and displaying recorded Therefore EtherCAT masters do not require a dedicated EtherCAT data traffic. communication processor. The master functionality puts hardly any load on the host CPU which can handle this task ■ Master implementation services easily besides processing the application program. Imple- EtherCAT masters have been implemented on a wide range mentation of an EtherCAT master can be very easy, partic- of RTOS, including but not limited to: eCos, INtime, MI- ularly for small and medium-sized control systems and for CROWARE OS-9, On Time RTOS-32, Proconos OS, Real-Time clearly defined applications. For example a PLC with a sin- Java, RT Kernel, RT Linux, RTCX Quadros, RTAI Linux, PikeOS, gle process image: if it does not exceed the 1,486 bytes, Linux with RT-Preempt, QNX, VxWin + CeWin, VxWorks, cyclic sending of a single Ethernet frame with the cycle Windows CE, Windows XP/XPE with CoDeSys SP RTE, Win- time of the PLC is sufficient. Since the header does not dows XP/XPE with TwinCAT RT extension and XENOMAI change at run-time, all which is required is a constant Linux. Master stacks are available as open or shared source header to be added to the process image and the result to projects, as sample code and as commercial software. Im- be transferred to the Ethernet controller. plementation services are also available from a variety of The process image is already sorted, since with vendors and for a variety of hardware platforms. Informa- EtherCAT mapping does not occur in the master, but in the tion about this fast growing offering can be found in the slaves – the peripheral devices insert their data at the re- Product Guide of the EtherCAT website [1]. spective locations in the passing frame. This further un- burdens the host CPU. It was found that an EtherCAT mas- ■ Master sample code ter entirely implemented in software on the host CPU uses Another possibility to implement an EtherCAT master is less of its processing power than much slower fieldbus sys- to use sample code which is available for a nominal fee. tems implemented with active plug-in cards – even servic- The software is supplied as source code and comprises ing the DPRAM of the active card puts more load on the all EtherCAT master functions, including Ethernet over host. EtherCAT. All the developer has to do is adapt the code, System configuration tools – available from several which was created for Windows environments, to the tar- manufacturers – provide the network and device parame- get hardware and the RTOS used. This has been done suc- ters including the corresponding boot-up sequence in a cessfully for a number of systems. standardized XML format.

■ EtherCAT in embedded systems What also has to be considered is whether the used bus In an embedded environment an EtherCAT Master imple- configuration is static or dynamic.When using EtherCAT as mentation has to fit some special requirements, which are communication technology between multiple embedded often conflicting. On one hand, a specific environment re- systems, there is often a special operating mode used stricts hard- and software properties, and on the other which is either the standard logical process data exchange hand, the application requirements have to be fulfilled. or a point-to-point type communication, where The hardware environment includes a broad variation slave stations are polled by acyclic commands and the of micro controllers (8, 16 or 32 bit) with different con- cyclic part is only used to keep the system operational. straints concerning endianness and alignment limitations, The main task for deciding which master solution to which a master needs to address.There is also a broad vari- use is to clearly define how to face those conflicting re- ation of different MAC chips used where a master has to quirements. The different options are to develop an own face different data access methods (DMA access, IO access, master solution, to adapt the master sample code to the Dual Port RAM access). A special objective in an embedded embedded environment or to purchase a commercially environment is often the lack of a hard disk drive and of available master solution. course the limited resources like Memory,CPU or bus band- The benefit of EtherCAT in an embedded environment width (when accessing the MAC). Another objective a mas- is the possibility to have a scalable master by using or ter should meet is a broad variety of different operating omitting some features or special protocols to meet the systems or in some cases even no operating system at all. environment concerning memory and CPU. This is possible If the same master software implementation shall run on because a master stack does not require a special hard- multiple of such different systems, the main requirements ware but can be implemented in software. EtherCAT pre- to the software are portability and footprint. serves space in your control unit because no additional in- Besides these different environments a system design- terface devices are needed. Furthermore it reduces power er has to consider which application requirements are to consumption because only an Ethernet MAC is needed and fulfill. These requirements are defined by the maximum no additional active I/O cards. On mass products the cost is number of slaves to be used, what kind of slaves are used always a matter of desire; here EtherCAT saves money be- with respect to the required slave protocols (e.g. EoE, CoE, cause standard MAC hardware (consumer market) can be FoE, SoE) and how much data has to be transferred per used. time period (cyclic/acyclic data volume and bus cycle rate).

■ Master-Implementation with one Process Image ■ Structure of Master Sample Code Control Task

Ethernet Header ECAT EtherCAT Datagram Ethernet

DAFrame SA Type Frame EtherCAT Data CTR Pad. FCS System HDR HDR HDR Device Description Configuration Tool Process Image (XML) Description (XML) (6) (6) (2) (2) (10) (0…1486) (2) (0…32) (4)

constant Header completely sorted Working Padding Bytes HDR Process Data (mapped) process data Counter: and CRC constant generated by Network Ethernet Description incl. Controller (MAC) Boot-Up (XML)

EtherCAT Master

Standard Ethernet MAC

■ Slave 20 EtherCAT Interface with FPGA (IDAM) Slave Evaluation Kit (Altera/EBV) Slave Evaluation Kit (Hilscher)

■ Slave architecture ■ Slave implementation services A cost-effective EtherCAT slave controller is used in the Several vendors offer slave implementation services in- slave devices. With EtherCAT the slave does not need a mi- cluding hardware and software integration. The various crocontroller at all. Simple devices that get by with an I/O EtherCAT Slave Controllers are supported by corresponding interface can be implemented only with the ESC and the evaluation kits. The Slave Evaluation Kit makes all the in- underlying PHY, magnetics and the RJ45 connector. The terfaces of the controller easily accessible. Since with process data interface (PDI) to the slave application is a 32- EtherCAT powerful communication processors are unnec- bit I/O interface. This slave without configurable parame- essary, the kit shown above contains an 8 bit μC which op- ters needs no software or mailbox protocol. The EtherCAT tionally can be used as host CPU. The kit comes with slave State Machine is handled in the ESC. The boot-up informa- host software – the equivalent to a protocol stack – in tion for the ESC comes out of the EEPROM that also sup- source code, and a reference master software package. Im- ports the identity information of the slave. More complex plementation workshops are held frequently. slaves that are configurable have a host CPU on board.This CPU is connected to the ESC with an 8-bit or 16-bit parallel interface or via a serial connection (SPI). The performance of the host CPU is determined by the slave application – the EtherCAT protocol software can be run additionally.The EtherCAT stack manages the EtherCAT state machine and the communication protocol: This means in general the CoE protocol and for supporting firmware download FoE. Optional the EoE protocol can be implemented.

■ Slave Hardware: EtherCAT Slave Controller with Host CPU ■ Slave Hardware: EtherCAT Slave Controller with direct I/O

Host CPU HTTP, RAM for TCP/IP FTP, … and complex Applications Process Data Service Data TCP/IP (optional) 8 I/O 8 I/O 8 I/O 8 I/O

EtherCAT EtherCAT Application Mapping Slave I/O Application Slave Controller Controller Process Data Mailbox Process Data Service Data Dual Port Memory non volatile Data EEPROM Dual Port Memory non volatile Data EEPROM

SYNC-Manager, FMMU Registers SYNC-Manager, FMMU Registers

Auto-Forwarder Auto-Forwarder with Loop Back with Loop Back EtherCAT MAC EtherCAT MAC EtherCAT MAC EtherCAT MAC MII MII MII MII

PHY PHY PHY PHY RJ45 RJ45 RJ45 RJ45 Trafo Trafo Trafo Trafo

Slave Evaluation Kit (Beckhoff) Slave Evaluation Kit from Beckhoff 21

■ EtherCAT Slave Controller ■ The parallel 8/16-bit microcontroller interface corre- Several Manufacturers provide EtherCAT Slave Controllers. sponds to conventional interfaces for fieldbus con- Slave controller functionality can also be implemented trollers with DPRAM interface. It is particularly suitable very cost effectively on FPGAs, for which binary code as for more complex devices with larger data volume. well as IP cores are available as buy-out license. The slave Controllers typically using this interface are e.g. Infi- controllers typically feature an internal DPRAM and offer a neon 80C16x, Intel 80x86, Hitachi SH1, ST10, ARM or TI range of interfaces for accessing this application memory: TMS320 series. ■ The 32-bit parallel I/O interface is suitable for the con- ■ The serial SPI (serial peripheral interface) is intended nection of up to 32 digital inputs/outputs, but also for particularly for devices with small process data quanti- simple sensors or actuators operating with 32 data bits. ty, such as analog I/O modules, sensors, encoders or Such devices do not need a host CPU at all. simple drives. This interface is typically used with 8 bit controllers, such as Microchip PIC, dsPIC, Intel 80C51, Latest information on the choice of EtherCAT Slave Con- etc. trollers can be found on the EtherCAT website.

■ EtherCAT Slave Controller overview

Name ET1100 ET1200 ET18xx netX 5 netX 100 netX 500 netX 50 Type ASIC ASIC Configurable IP Core ASIC ASIC ASIC ASIC HW Supplier Beckhoff Beckhoff Altera/Xilinx Hilscher Hilscher Hilscher Hilscher Package BGA128 QFN48 FPGA dependent BGA201 BGA345 BGA345 PBGA324 0,8mm pitch 0,5mm pitch 0,8mm pitch 1mm pitch 1mm pitch 1mm pitch Size 10 x 10 mm 7 x 7 mm FPGA dependent 13 x 13 mm 22 x 22 mm 22 x 22 mm 19 x 19 mm μC Interface serial/parallel serial* serial/parallel serial (SPI), μC bus μC bus μC bus (8|16bit) parallel (8|16bit)*" AVALON®/OPB®* (8/16/32, async) (internal, 32Bit) (internal, 32Bit) (internal, 32Bit) Digital I/O 8-32* 8-16* 8-32* 16 - - - General Purpose I/O 0-32* 0-12* 0-128* - 16 16 32 DPRAM 8 kByte 1 kByte 1...60 kByte* 6 kByte 256/400 Byte 256/400 Byte 6 kByte (Mailbox/ (Mailbox/ Process Data) Process Data) SyncManager Entities 8 4 0…8* 8 4 4 8 FMMU Entities 8 3 0…8* 8 3 3 8 Distributed Clock Support yes yes yes* yes yes yes yes No. of Ports 2–4(MII/EBUS)* 2–3 2 (MII/RMII) 2 x MII 2 (100BaseTX) 2 (100BaseTX) 2 (100BaseTX) (EBUS/ max. 1 x MII)* Specials Routable with Various licence Multi Protocol Multi Protocol Multi Protocol Multi Protocol standard PCB models are Support Support, Support, Support, available. A wide Integrated PHYs, Integrated PHYs, Integrated PHYs, range of Xilinx Integrated μC Integrated μC Integrated μC and Altera FPGAs (ARM9-200MHz) (ARM9-200MHz) (ARM9-200MHz) is supported. *configurable

■ Conformance and Interoperability

Conformance and interoperability are very important factors for the success of a communication technology. Therefore the EtherCAT Technology Group is taking these topics very seriously. Conformance of the technology implementation with the specifications is the prerequisite of interoperability, which means that devices of different manufacturers co-operate within the same networked application.

22 EtherCAT Technology Group

In order to achieve both, the ETG initially started with a conformity of EtherCAT drives supporting the CiA402 drive pragmatic approach: the Plug Fests. In addition to these in- profile: easy set up, identical behaviour and correct support teroperability meetings there is the Conformance Test Tool of cyclic synchronous operation modes are part of these (CTT). For product certification official EtherCAT Test Cen- tests. ters (ETC) have been established. To meet minimum conformance requirements a device has ■ Plug Fest to pass the protocol test using the Conformance Test Tool Plug Fests – typically these are two-day events – are meet- at the time of its first release to the market. Of course ven- ings where master and slave device suppliers gather to test dors are encouraged to keep up with the latest version of and improve interoperability, to share implementation tips the Conformance Test Tool and also fix issues which only and tricks and clarify questions regarding the technology. have been revealed after the initial release of their device. The Plug Fests have established themselves as pragmatic The Conformance Test Tool is licensed on a subscription ba- and effective means to achieve interoperable EtherCAT sis, in order to ensure long term availability of resources for products. They are typically attended by 20 or more device maintenance, support and enhancement. EtherCAT device vendors, representing 50+ different products. ETG organiz- vendors have to maintain a valid subscription of the tool. es EtherCAT Plug Fests in Europe, Asia and North America. The test cases are developed and maintained by the ETG Working Group Conformance. ■ Conformance Test Tool The Conformance Test Tool allows one to check protocol ■ Working Group Conformance compliance. Besides a standard PC with a standard Ether- The Technical Committee of the ETG established the Work- net adapter, the MS Windows based Conformance Test Tool ing Group Conformance, which defines the test procedures does not require any special hardware. The EtherCAT and in particular works on continuously enhancing and im- frames to stimulate the Device under Test (DuT) are sent proving the tests.The main goal of the working group is to and received via a standard Ethernet port. The tool reads reach complete test coverage in the future. the test cases from an XML file, so that test enhancements The Working Group Conformance meets regularly, either in can be generated without modifications to the test tool face-to-face or web meetings. software itself. Test results and comments are shown in a test logger. The tool also tests the EtherCAT Slave Informa- tion (ESI) file. CiA402 tests for example allow one to check

EtherCAT Technology Group 23

■ EtherCAT Test Center ■ Interoperability Test The ETG has accredited official EtherCAT Test Centers (ETC) This test is performed using a network with a diverse com- in Nuremberg, Germany, and Kyoto, Japan. Further test bination of EtherCAT devices. Such networks are main- centers in Europe, Asia and North America are intended. tained and constantly enhanced at the EtherCAT Test Cen- ETCs do not only perform the official EtherCAT Confor- ter. mance Test, but also provide qualified feedback and implementation support for ETG members. Furthermore, ETCs ■ Conformance Certificate provide facilities for the interoperability test. If a device passes the official EtherCAT Conformance Test at an EtherCAT Test Center, ETG issues the Conformance Cer- ■ EtherCAT Conformance Test tificate. Devices for which a Conformance Certificate has The EtherCAT Conformance Test covers a Conformance been issued are EtherCAT Conformance tested products. Test, Interoperability Test and Physical Layer Test carried They may carry the official EtherCAT Conformance Tested out by an ETC. Using the Conformance Test Tool already en- Logo and they are marked accordingly in the EtherCAT sures a high degree of conformity. However, since test tool Product Guide. EtherCAT users are encouraged to include results of tests carried out in the R&D lab are not checked the availability of the conformance test mark in their ven- by an independent body the EtherCAT Conformance Test is dor and device selection process. executed by the ETC, too. Vendors who want a Confor- mance Certificate submit their devices for testing at an of- More information about Conformance is available at ficial EtherCAT Test Center of their choice. http://www.ethercat.org/en/conformance.html Test Agenda of the EtherCAT Conformance Test: | EtherCAT Protocol (Conformance Test) – ESI, SII (EEPROM), EtherCAT State Machine, Mailbox Communication and Services | Indicator Specification | Marking Rules | CiA402 Drive Profile (if supported) | Interoperability Test

■ Safety over EtherCAT

In the interest of realizing safe data communication over EtherCAT, the Safety over EtherCAT protocol has been disclosed within the EtherCAT Technology Group. Safety over EtherCAT meets the requirements of IEC 61508 SIL 3 and enables the transfer of safe and non-safe information on the same communication system without limitations with regard to transfer speed and cycle time.

24 EtherCAT Technology Group

■ Safety fieldbus system The following errors for such a network have to be as- Intelligent safety solutions in the automation components sumed: corruption, repetition, interchanging, loss, delay,in- and communication systems enable integration of safety sertion, masquerading and invalid addressing of mes- technology into the machine design. sages. A safety protocol must be able to handle all these er- One of the key factors enabling this kind of integration rors via suitable measures, i.e. they must be detected ac- is the transfer of safety-related and standard communica- cording to the required safety category. tion on the same fieldbus. The solution for EtherCAT is the Safety over EtherCAT protocol. The following features were crucial in the development of the Safety over EtherCAT protocol: The benefits: | Compliance with Safety Integrity Level SIL 3 of | Single communication system for control and IEC 61508 safety information | Safe and non-safe information on the same | Seamless integration of the safety concept into the communication system machine design | Independence of the protocol from the transfer | Outstanding diagnostic options for the system and medium safety functions | The length of the safe process data is not restricted | Flexible extension options by the protocol | No performance limitations in terms of real-time | Very short frame lengths are possible and determinism | No limitations with regard to transfer speed | No separate development tools for standard and and cycle time safety application | Simple handling and transparent safety functions The Safety over EtherCAT protocol has been assessed by German Technical Inspection Agency (TÜV). It is certified as ■ Technology Requirements a protocol for transferring process data between Safety The basic principles for testing and certification of bus sys- over EtherCAT devices up to SIL 3 according to IEC 61508. tems for transferring safety-related messages are specified The implementation of the Safety over EtherCAT protocol in the international IEC 61784-3 standard. in a device must meet the requirements of the safety tar- get. The associated product-specific requirements must be taken into account.

■ Safety fieldbus systems enable simple and flexible machine concepts ■ Safety over EtherCAT Frame

PLC PLC

Fieldbus Standard fieldbus Standard Standard I/O I/O

Relay logic

Safety Safety/ inputs standard I/O

Safety logic Safety/ standard I/O Safety outputs Safety logic

Standard Safety drives drives

M M M M M M M M M M

EtherCAT Technology Group 25

Any communication path can be used, including fieldbus vices detects a communication error, it changes to reset systems, Ethernet or similar transfer systems, optical fibre state, thereby resetting the connection. cables, copper cables, or even radio links. ■ Application Example ■ Implementation aspect The safety and functionality of a safety communication EtherCAT is used as a single-channel communication sys- protocol can only be proven through implementation in a tem for transferring safe and non-safe information. The product. Devices with Safety over EtherCAT have been transport medium is regarded as a “black channel”and not available since 2005. EtherCAT is therefore one of the first included in safety considerations. A safety frame contain- Industrial Ethernet real-time communication systems sup- ing the safe process data and the required data backup is porting a safe protocol. included in the EtherCAT process data. This “container” is Applications utilize the benefits of the technology. analyzed in the devices at the safety application level. The Scalable safety-related input and output components can communication remains single-channel. be used in the system; additional inputs or outputs can be Via suitable procedures, the frame is designed such extended flexibly using safety and non-safety devices as that a minimum container length of 6 bytes is sufficient required. for transferring all error detection information, including Even the safety logic can be embedded within the net- one byte of safe process data. Incidentally, the protocol work.The control PLC then remains a standard device with- does not impose any limits regarding the length of safe out safety extension and the safety logic is processed with- process data. This means that safety components with a in a safety device in the network segment. This saves costs large amount of safe process data are also supported. and enables scaling of the safety logic within the system. During start-up of a Safety over EtherCAT connection, a Only the messages between the Safety over EtherCAT mas- state machine is processed both in the master and in the ter and the corresponding safety slave devices are routed slave. Here again, the focus was on a simple structure in or- via the standard PLC. Of course the classical safety PLC ar- der to make implementation as simple as possible. State chitecture is supported by Safety over EtherCAT as well. transitions are initiated by the master and acknowledged With the black channel approach even the concatena- by the slave. tion of machine parts is possible. The Safety over EtherCAT The “data” state is the normal operating state for ex- Frames are routed via the standard communication path changing safety input and output data. If one of the de- on the Process Control level.

■ Black channel approach allows concatenation of machine parts ■ Safety over EtherCAT hardware architecture ■ Simple state machine for a master/slave connection

Maschine | A Maschine | B Maschine | C

Ethernet

Safety-over-EtherCAT Safety-over-EtherCAT

#1 #2 #3

■ Why do companies choose EtherCAT?

26 EtherCAT Technology Group

Photo: BMW AG

■ High Performance ■ Flexible Topology EtherCAT is the fastest Industrial Ethernet technology with The machine structure determines the topology - not the outstanding synchronization features. It is used in all ap- bus system. Since no switches or hubs are needed, they do plications with short cycle times like Motion Control appli- not limit the network structure. There are almost no re- cations as well as for measurement applications with strictions given by the EtherCAT technology: line, tree, star, many I/O signals. drop lines - everything is possible. Simply the use of EtherCAT allows one to increase the The automatic link detection gives the possibility to control performance up to 20%, often even more. This per- support hot-swap functionality of machine parts. The formance is then available for the user application. The in- (dis-)connection of the parts can be managed by the bus creased accuracy and productivity of the machine leads to manager or can be handled automatically by the slave lower costs and higher profits. EtherCAT meets today's and devices. tomorrow's requirements! With a simple extra cable to a second (standard) Ether- net port on the EtherCAT master, a very simple and cost ef- Application examples: fective network redundancy is possible. ■ Robotics EtherCAT is also ideal for widely distributed applica- ■ Machine tool applications tions: Up to 100 m between two nodes on copper cables and ■ CNC functionality up to 2 km on standard fiber-optic cables are supported. ■ Packaging machines ■ Injection molding Application examples: ■ Engine test beds ■ Baggage conveyor systems ■ Measurement applications ■ Bridge absorption system ■ Ultra fast metal cutting ■ Snow blower control ■ Blow molding machinery ■ Automated warehousing ■ Semiconductor + FPD manufacturing ■ Printing machines ■ Hydraulic/electric presses ■ Woodworking machines

EtherCAT Technology Group 27

■ Ease of Use ■ Low Cost The configuration and maintenance of a machine is a deci- EtherCAT meets or even undercuts fieldbus cost levels. sive factor for the life cycle costs. With EtherCAT, these There is no special master card required on the master side tasks are significantly simplified. The configuration and – on-board MAC or low cost standard NIC are sufficient. For the topology of a machine can be scanned after installa- the slave side, highly integrated slave controllers guaran- tion and can be compared to an expected configuration. tee low interface costs. Furthermore, between the master If a device has a failure or detects errors on the com- and the slave standard Ethernet cables can be used. No ac- munication systems, the outstanding diagnostic features tive infrastructure components are required and therefore give an exact localization of the error source and therefore no costs for buying, configuration, installation and main- allow a fast trouble shooting. tenance of these devices are necessary. Again the performance of EtherCAT is decisive: There is no need for network "tuning", as known for standard field- Application examples: bus systems. If additional information is needed from a de- ■ Embedded systems vice, it can be added to the cyclic transfer (nearly) without ■ Frequency inverters limitations by the network bandwidth. ■ Sensors ■ Mass flow controller Application examples: ■ Encoder ■ Standard PLC applications ■ RFID reader ■ Automotive factory automation with short MTTR (Mean time to repair) ■ Intra-machine communication with expected hardware configuration ■ Modular machines ■ Welding machines ■ Edge banding machines

■ Contact: ETG Office North America ETG Office Japan Volente, Texas, USA Tokyo, Japan

ETG Headquarters Phone: +1-877-ETHERCAT Phone: +81 (3) 5825 5333 Ostendstraße 196 Fax: +1 (512) 535 1437 Fax: +81 (3) 5825 8550 90482 Nuremberg Email: [email protected] Email: [email protected] Germany Phone: +49 (911) 5 40 5620 ETG Office China ETG Office Korea Fax: +49 (911) 5 40 5629 Beijing, P. R. China Seoul, Korea www.ethercat.org Email: [email protected] Phone: +86 (10) 66 21 7688 Phone: +82 (2) 21 07 32 40 Fax: +86 (10) 66 21 0992 Fax: +82 (2) 21 07 39 69 Email: [email protected] Email: [email protected] 28 EtherCAT Technology Group

EtherCAT®, Safety over EtherCAT™, are trademarks or registered trademarks. Other designations used in this publication may be trademarks whose use by third parties for their own purposes could violate the rights of the owners.