Editor's Choice


Nick Denbow’s European report: The rise of an Ethernet fieldbus

October 2015 Editor's Choice News

Remember the 'Fieldbus Wars'? These happened in the 1990s I suppose, when there were all sorts of sensor networks used to gather data from the many sensors distributed around a plant or machine, to transmit information back to a central point, a controller or processor. That point was where human access was allowed, to monitor the plant, and maybe adjust the control system instructions. It seemed then that each industry, and each country, had its own preferred system to submit for consideration as an International Standard. IEC61158 duly emerged, with a classic compromise, specifying 8 protocol sets or technologies that can be used for fieldbus communications.

Max Felser, of the University of Applied Science Berne, wrote a paper in around 2000 entitled 'Fieldbus Standards: History and Structure', in which he concluded that: “It is now up to the market to decide which ones will be used and gain large acceptance, not the standards bodies”. Then came the Internet, with vastly improved communications, and for the process industry at least the marketing hype and pressure behind the US-based Foundation fieldbus seemed to swamp the more formal technical approach from Profibus. The process market swung towards FF, and the wars seemed to be over when Siemens also joined the FF committees: so much so that even Emerson produced sensors with Profibus interfaces, and actually started using the word 'Profibus'. The ultimate accolade came when James Powell, of Siemens/Milltronics, editor of the textbook 'Catching the Process Fieldbus' (which is about Profibus) was invited to speak at an Emerson Exchange User Conference!

Then there were voices in the background, muttering about IT systems, the Internet, Ethernet and so on. Jim Pinto first talked about it in 1999, and 14 years later, said the same things, with more force and justification. His view has always been that Ethernet is the way to go, and recently has suggested that PI, ODVA, CANopen, Modbus and FF have all tried to embrace it, in their different ways. This year, the Siemens website has a page that encourages all their Profibus customers to consider changing to Profinet now – as most of them are not in hazardous areas, presumably. Siemens comment that “Profibus has been established for years as the fieldbus for machines and plants. Based on serial bus technology, it revolutionised the automation world in the ’80s, and created for the first time the foundation for the distributed concepts common today. In the ’90s, Ethernet spread into IT and industry. Today, manufacturing is inconceivable without both systems. But would it not be more efficient to combine the advantages of both systems? The answer to this question is Profinet. It merges the industrial experience of Profibus with the openness and flexible options of Ethernet.

So needless to say, PI has also announced the same thing, and is pushing for Profinet to become the choice for engineering projects of the future. The recent PI conference in the UK explained that PI is pushing forward (via German industrial research and university contacts presumably) to enable Profinet devices to be (1) used in hazardous areas, and (2) use two-wire technology (for power and data). Also announced at this conference was that the same Profibus PA Device profile V3.02 is to be useable on devices working in both Profibus and Profinet systems, and James Powell demonstrated how an engineer adding a device to a controller on a Profibus network will use the same approach, when he adds a similar device to a Profinet network in the future.

PI training of engineers

Profibus International (PI), the umbrella organisation covering Profibus and Profinet technology, has established Profibus Competence Centres (PCCs) in most countries. This could be described as a German style of business, where technology centred co-operation and investment between companies and universities (and maybe government too) comes from a focus on mutual future benefit. In the UK they have worked with Manchester Metropolitan University, where the Automation Systems Centre provides short courses, consultancy, feasibility studies and software development for control systems. As a certified Competence Centre for both Profibus and Profinet systems, it delivers accredited courses for the automation community, covering the skills needed by installers, maintenance technicians and engineers working on plants with such systems installed. One of the original tutors, Andy Verwer, set up his own consultancy, VerwerTraining.com, to provide similar services, and Andy has been instrumental in spreading this approach around the English speaking world in particular, including to South Africa, where he helped the SA Regional Profibus Association (now renamed PI SA) start a similar approach, with a PCC and training courses – which are now run by IDXonline.com. These centres enable engineers to obtain professional qualifications in Profibus engineering. At Verwer Training, Andy has just completed the development of a new Certified Profibus System Designers course for worldwide use by PI, for system integrators and designers who are planning Profibus network designs. Following PI certification, the first such course run by Verwer Training was held earlier this year in the UK, using the facilities of the new Endress+Hauser training centre in Manchester, and PI plans now to expand this internationally.

The groundwork and training being done by PI, in co-operation with universities and training centres, establishes a method of recognising industrial skills for engineers and technicians that has perhaps been overlooked over recent years.

Nick Denbow spent 30 years as a UK-based process instrumentation marketing manager, and then changed sides – becoming a freelance editor and starting Processingtalk.com. Avoiding retirement, he published the INSIDER automation newsletter for five years, www.iainsider.com, and now acts as its EMEA editorial correspondent. His blog is on www.nickdenbow.com





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