Speaking at the EU OPC Foundation roadshow in Paris last month, president Thomas Burke traced the history of what originated as OLE for process control back in 1995. Since then, OPC has grown to become the ‘interoperability standard for a connected world.’ OPC has more members and take-up in the EU than in any other region. While the Microsoft COM/DCOM technology was ‘a good idea at the time,’ it has proven complex, insecure and has shut out some markets. DCOM was tried in the PLC environment but ‘it did not work.’ Notwithstanding the misgivings, classic OPC was a resounding success with an estimated installed base of 40 million devices. By 2004, with the wide take up of XML, it was ‘time to push the reset button.’ Work began on the new Universal Access (UA) spec, standardizing on the message rather than on lower level protocols. OPC is ‘the open alternative architecture to closed proprietary systems.’ OPC-UA extricates the standard from the Microsoft world to enable more platforms, applications and vertical integration.
OPC-UA is scalable from embedded systems to the mainframe and is key to multi-vendor interoperability. Along with Microsoft platforms, OPC spans servers, SCADA systems, Linux and smart phones. SAP ‘may not be the best client,’ but OPC-UA is the basis of SAP’s device-level interoperability. Most all automation vendors are on board.
Michel Condemine (4CE-Industry) who heads-up the French branch of OPC observed that the COM version of OPC only addressed the ‘easy’ problems, and had too large a footprint (20 meg RAM) for embedded systems. Despite the move away from a Microsoft only environment, Condemine appears to believe that more can be done to ‘open’ the spec. Hence the joint industry project to develop an open source (but not, ‘free!’) IT stack to support the higher level protocol. A group of French companies (Areva/Euriware, EDF, 4CE and Schneider Electric) are engaged on a joint project to develop a complete stack for Windows (including CE) and various Linux systems. The aim is for a compact (under 500k) code base that runs across all platforms along with a reference implementation for a ‘mainstream’ OPC UA server. The C++ code is developed outside of .NET/Visual Studio to make it ‘information model independent’ and nonproprietary. Security and regulatory compliance is assured by PKI certificates and a certification authority.
In the Q&A, Condemine was asked, how ‘real’ was OPC-UA in the face of the huge installed base of ‘vanilla’ COM-based OPC. He assured the audience that Siemens, Schneider Electric and others all use OPC-UA today. Legacy OPC can be ‘wrapped’ to turn them into UA servers. Areva’s wind generators have OPC UA servers inside. SAP has a true UA client. Just as COM is dead, so is vanilla OPC. UA is the ‘route to the future.’
While the Open UA project delves deeper into the infrastructure, another project, the ‘Meta model’ sets out to occupy the high ground—federating the information models of different plant communities. Target domains include ISA S95, S88, IEC 61850, 61970, Bacnet, Mimosa and EDDL. Here collaboration is planned with Mimosa/OpenO&M, S88/95, OAGiS and more. Sparx Systems’ Enterprise Architect is the development tool of choice.
Claude Gomez (SciLab Enterprises) presented SciLab’s work on a free and open source scientific calculator. The computation engine can be embedded into applications providing a high level language, hundreds of math functions, data structures and user defined types. Matrix computations and simulations are also included. Math teachers use it, ‘so it must be easy!’ The SciLab project has backing from the French Petroleum Institute (IFP). An ‘Enterprise’ edition adds support and training.
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