Ladder logic auto translation to 61131-3 function block

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Thread Starter

Neil Crompton

Does anyone know what company manufactures this product and is it for all types of plcs or just certain types. I have a great deal of old Allen Bradley plc5 and slc machines along with about 20 siemens S5s. I would like to upgrade but would prefer to shop around for the most suitable replacement products and to trust to a third party to rewrite all the code seems expensive and fraught with danger.
 
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Bill Clemons

Take a look at Altersys.com. One of their products, Isagraf, is designed to meet IEC 61131-3. Isagraf provides utilities for multiple control structures: Ladder, Function Block, Structured Text, and some conversion utilities, also. The compiled code can be targeted for PC based applications and down to Flash memory controllers like Net Arm series. The designer package operates on XP along with full simulation environment, literally minutes to get development phase tasks started.
 
Automated code translation is in itself an area fraught with danger, allied to impractical goals and disappointment when expectations are not realised.

Personally, I would take that "100% accuracy" with a very large pinch of salt. Accuracy to what? It's like saying I can convert a horse to a car. They may ('may') achieve similar things in terms of personal transport, but they do them in very different ways.

All code converters I've come across work at a non-context-sensitive level. They convert instruction-by-instruction, or if you're really lucky, network-by-network. The idea of a code converter reading a lovingly crafted piece of old ladder logic covering several networks and realising that this can now be achieved using a single IEC-defined function is nil. If all you've got is simple binary logic, I would guess that a converter will be able to rename and renumber the contacts and coils in keeping with IEC doucmentation standards. But please, please, please, don't look for a product which takes badly written spaghetti code and magically transmutes it in to well-ordered structured code using what are currently accepted as good software development techniques. It ain't gonna happen!
 
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Vladimir E. Zyubin

Neil, it seems you are locked in Siemens' solution... Most of the IEC 61131-3 products (if not all) have no "cross-brand" portability... This problem is an inseparable part of the standard.

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Best regards.
Vladimir E. Zyubin mailto: zyubin @ iae.nsk.su
 
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neil crompton

Ken,

We now have a translation tool that will convert ladder to function block. It can also recognise network patterns and build suitable function blocks or replace them from a client library.

Further software tools test the code one against the other network by network. We recently updated code from a Triconex TMR safety PLC to 1131 on an off shore facility for BP and hope to develop drivers for Siemens, Modicon and Rockwell.

Will gladly give you more information should you require it.

[email protected]
 
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