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IEC 1131-3 programming -ISAGRAF
Back to standards for RTU's

Many organisations have SCADA systems which must be installed over time through reasons of logistics, budgets, and various other reasons. Competitive tendering can result in the delivery of several discrete SCADA systems, which must eventually integrate. This will involve multiple vendors and they face problems due to the SCADA industry's use of proprietary hardware, software and communications protocols.

To overcome this it is necessary to specify standards for the Remote Terminal Unit in telemetry applications (SCADA). The aim is to provide a standard specification for hardware and software of an RTU. The resultant RTU should be suitable for a large variety of applications from small point to point systems to large scale distributed networks including interface to SCADA networks.

The RTU will be programmable using the IEC-1131-3 programming languages, and will use DNP3.0 as a communications standard. It has been surprising to see that very few standards need to be enforced to achieve interoperability of equipment, but additional standards are needed to achieve portability of software.

This will allow multiple vendors to participate in a SCADA program, without building a Tower of Babel.

Ian Wiese email

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IEC 1131-3 programming

For anyone interested, you may find it worthwhile to contact CJ International, and enquire about their ISAGRAF product. This provides the full set of IEC-1131-3 languages, and is a very impressive implementation. It is aimed at embedded systems.

They have a web site at Isagraf and can be contacted at

86 Rue de la Liberte
F-38180 SEYSSINS Phone 76 48 99 06 Fax 76 96 43 54.

Ask for their demo disk. (or email me - I don't think they will mind) They are very prompt. .


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