IEC 61131-3 PLC programming Standard

[sidluvj]

i am supposed to write a PLC program using the IEC 1131-3 standard. if i write it using the mitsubishi GX IEC developer will i be able to use the same program in siemens S7 and allen bradley PLCs. or is there conversion software available.

 

[Ken M]

It depends on how closely each of the manufacturers you have mentioned adhere to the standard. The IEC have no interest themselves in policing the standard with the result that an organisation called PLCOpen has taken on the task of defining test procedures for evaluating programming software. They award various certificates of compliance for the different IEC-61131-3 languages.

However, two manufacturers could create language editors which both meet all the requirements of the standard, but then add in some extra features or instructions not defined by the standard. If you stick to using the basic set of instructions you may be able to recompile a source file to be used in either package. But as soon as you stray in to the 'specials' there may be no corresponding instruction in the other's language to handle this.

There is certainly no possibility whatever of taking a Mitsubishi program in its entirety and loading it in to Siemens or Rockwell PLCs. At best you may be able to take certain code elements or block structures and recompile them within Siemens' or Rockwell's environment.

Regards

Ken

 

[JesperMP]

For Siemens, only the "languages" SCL and GRAPH conforms to the IEC standards.
The more commonly used STL, LAD and FBD do not.

 

[ayman metwally]

For Siemens, only the "languages" SCL and GRAPH conforms to the IEC standards.
The more commonly used STL, LAD and FBD do not.

Siemens doesn't follow the standard!!
That surprises me.

Is this common for other PLC's manufacturers?

 

[sidluvj]

IEC 61131-3 PLC programming standards
The PLCOpen organisation: which PLC manufactures have been awarded compliance certificates and to what degree?

 

[Ken M]

Certification covers 5 languages and several different levels in each. No-one has got complete certification. In many cases the test specifications have not even been written yet.

Try http://www.plcopen.org/ for more info.

When the standard originally emerged many years ago, manufacturers had to decide whether to throw out everything they had done up to that point and start again, or stick with what they had and adapt it. For some languages like Structured Text there wasn't a high level of previous use so generating a new editor to comply with the standard didn't upset manufacturers or their existing customers too much. However for Ladder or Instruction List, everyone already had their own dialect and the larger an installed base a manufacturer had the more reluctant you can understand them being about changing.

Whether the standard is a good standard or not is one discussion. Whether it will ever overcome the inertia of existing systems is a completely different one.

regards

Ken

 

[marwanco]

Siemens S7-200 Micro/Win software has IEC 61131-3 Option.