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A Comparison Between Fieldbuses and Remote I/O for Instruments in the Process Industry

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A Comparison Between Fieldbuses and Remote I/O for Instruments in the Process Industry 2007:010 CIV MASTER'S THESIS A Comparison between Fieldbuses and Remote I/O for Instruments in the Process Industry Lars Persson Luleå University of Technology MSc Programmes in Engineering Electrical Engineering Department of Computer Science and Electrical Engineering Division of EISLAB 2007:010 CIV - ISSN: 1402-1617 - ISRN: LTU-EX--07/010--SE Abstract New technology arises in all areas. Some just last for a few years before someone else devel- ops a better technology. This makes it hard to decide whether and when to use new technol- ogy. Being a contractor for the process industry, like Outokumpu Technology, does not make it easier to decide since these systems usually runs for at least 15 years. The aim for this Thesis is to provide information about fieldbus technology for the process industry. Although it has existed for several years far from everyone uses it. The Thesis focus on fieldbuses at instrument level. The knowledge, both of the contractor and the buyer, is of great importance. Both advantages and disadvantages have been identified with fieldbuses that can be used to decide whether to use fieldbuses or not. The examiner of this Thesis was Per Lindgren at Luleå University of Technology I II Preface This Master’s Thesis is the final part required for my Master of Science degree in Electrical Engineering at Luleå University of Technology. The work has been carried out during the winter 2005/2006 at Outokumpu Technology AB in Skellefteå. The aim with this Thesis is to identify advantages and disadvantages with fieldbus technology in Industrial applications. I would like to thank the following persons who have helped me with this Thesis: my supervi- sor Pär Norman at Outokumpu Technology for his time, support and ideas; Leif Nyberg, Manager of the Electrical and automation department at Outokumpu Technology and Per Lindgren at LTU for allowing me to do this Thesis; Leif Karlsson from ABB who has an- swered a lot of my questions; Jan Östensson, Mats Näätsaari and Jan Malmström at Husum and Magnus Normell at Eurocon for the interviews; my sweet girlfriend Freja for proofread- ing and correcting my English; and finally the rest of the staff at Outokumpu Technology for help and support throughout the work on this Thesis. Skellefteå, 17th December 2006 Lars Persson III IV Table of content 1 Introduction ........................................................................................................................... 1 1.1 Background ...................................................................................................................... 1 1.2 Purpose............................................................................................................................. 1 1.3 Delimitations .................................................................................................................... 1 1.4 Outokumpu Technology AB, Skellefteå .......................................................................... 1 2 Method.................................................................................................................................... 3 2.1 Literature review .............................................................................................................. 3 2.2 Interview........................................................................................................................... 3 2.3 Test system....................................................................................................................... 3 3 Literature review................................................................................................................... 5 3.1 Communication levels in a plant...................................................................................... 5 3.2 History.............................................................................................................................. 5 3.3 Fieldbus in general ........................................................................................................... 7 3.4 4-20 mA vs. fieldbus instrument technology ................................................................. 10 3.5 Wireless fieldbus............................................................................................................ 11 3.6 Description of Profibus, Foundation Fieldbus, DeviceNet and Interbus ....................... 13 3.7 Practical experience from fieldbus installations............................................................. 22 4 Interview .............................................................................................................................. 27 4.1 Background .................................................................................................................... 27 4.2 Result.............................................................................................................................. 27 5 Test system........................................................................................................................... 31 5.1 Background and problem ............................................................................................... 31 5.2 Material .......................................................................................................................... 32 5.3 Method ........................................................................................................................... 34 5.4 Result.............................................................................................................................. 34 5.5 Problems......................................................................................................................... 41 6 Result.................................................................................................................................... 43 6.1 Comparing fieldbuses with remote I/O .......................................................................... 43 6.2 Requirement of knowledge ............................................................................................ 43 6.3 Differences between Foundation Fieldbus H1 and Profibus PA.................................... 43 6.4 Wireless fieldbuses......................................................................................................... 44 7 Discussion and Conclusion ................................................................................................. 45 8 Future work ......................................................................................................................... 47 References ............................................................................................................................... 49 Appendix A: AS-Interface (Actuator-Sensor Interface) Appendix B: Test system specification Appendix C: GSD file Appendix D: Interview questions Appendix E: Abbreviations V VI 1 Introduction 1.1 Background The society is constantly developing and changing and therefore we have to adapt to the changes. The automation of metal process industry is no exception. The 4-20 mA analogue standard for instrumentation is still used at most plants in Sweden, but the standard has been around since the 1960’s. However, the time of change seems to have reached the process in- dustry as well. In the early 1990’s, digital communication between instruments and the con- trol system began to develop. Still, new developments, improvements and changes are made every year, making it problematic to decide when to invest time and money into the new sys- tems. It has to be taken into consideration that a control system for the process industry runs for at least 15 years. The research question of this thesis is: is it time for new technology to take over? 1.2 Purpose Outokumpu Technology AB in Skellefteå (OTSk) is currently trying to decide whether the company should learn how to use fieldbuses and recommend it to their costumers. A fieldbus is like a data bus where several devices are connected to the same cable and communicate through digital messages. If the answer to the previous question is yes, which fieldbus should be used? Should OTSk recommend different fieldbuses depending on for example where in the world the installation is taking place? To facilitate the decision, OTSk wants to know which advantages fieldbuses can give regarding installation, operation and maintenance. Ad- ditionally to this, this thesis includes a limited search of wireless fieldbus solutions. The thesis will 1. Identify advantages and disadvantages with fieldbuses compared to remote I/O 2. Describe the differences between the fieldbuses 3. Identify advantages and disadvantages with wireless fieldbuses and make a study of wireless products and their manufacturers. The purpose is not to give a recommendation, but to provide data for decision-making. 1.3 Delimitations Due to time limits, the thesis will only look at four different fieldbuses for field devices. These are DeviceNet, Foundation Fieldbus H1, Interbus and Profibus PA. This thesis will then focus on two of them, Foundation Fieldbus H1 and Profibus PA, since these are operat- ing at the instrument level. To know more about how a fieldbus functions in a plant, visits will be arranged to Husum and ETEK. Interviews will be performed with installation, maintenance and operation personnel at both plants. They are both located near Örnsköldsvik in Sweden. A system was provided by OTSk to evaluate Profibus PA. It included
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