In reply to Ken Emmons Jr.: To address a couple of your points.

- The application "bloat" that you see in some IEC 61131-3 implementations is likely due to the fact that some manufacturers implement IEC mode by emulating it on their proprietary instruction set, rather than supporting it natively. I haven't seen anything in IEC ladder or IL that should make it inherently slower or larger.

- IEC 61131-3 does have a textual programming language. It has a Pascal-like rather than C-like syntax, but it does exist. I've never had a use for it, so I can't comment on what it is like to work with.

 

IEC 61131-3 has TWO textual programming languages. The second one has an assembler-like syntax.

Best regards,
Vladimir E. Zyubin

 

You might want to review TwinCAT v2.10 from Beckhoff Automation:

http://www.beckhoff.com/english/twincat/default.htm

We have an excellent implementation of IEC 61131-3 programming and support all 5 defined languages.

* Software PLC for Windows NT/2000/XP
The TwinCAT PLC is programmed in accordance with IEC 61131-3 independently of the manufacturer. Online connections with PLC run-time systems around the world can be implemented with TCP/IP, via fieldbuses on the IPC.

* TwinCAT PLC programming system
TwinCAT PLC offers all the languages in the IEC 61131-3 standard and has a powerful development environment for programs whose code size and data regions far exceed the capacities of conventional PLC systems.

* Online connection via networks
Changes to programs or data are supported by a very powerful link to the run-time systems, which can also operate over a network. All the usual facilities of a PLC are available."

Dave Zimbrich
BECKHOFF AUTOMATION GmbH
Field Applications and Support Engineer
Central Region-USA

 

I'm very interested about the argument. Could you please suggest me a book among those you speak about?

Thanks very much.

 

Davide,

Try the following texts:

IEC 1131-3 Programming Methodology: Software engineering methods for
industrial automated systems, Flavio Bonfatti et al, ISBN 2-9511585-0-5
Programming industrial control systems using IEC 1131-3 Revised
edition, R. W. Lewis, ISBN 0-85296-950-3

Bob

Robert J. Dusza, Jr.
Project & Technical Support Manager
(V) 1-860-647-3219
(F) 1-860-647-3150
E-mail - [email protected]
Manchester Water & Sewer Dept.
125 Spring St. P.O. Box 191
Manchester, CT 06045-0191

 

It seems some PLC vendors in their attempt to jump on the IEC1131 bandwagon have taken hold of a 'loop hole' in the IEC 1131 standard.

The standard states (paraphrasing) 'if you are a little compliant with the intent or standard, then you can say you are compliant'. As you can well understand, this loose interpretation of the rules allows for almost any vendor in any capacity ot be 'compliant'. True compliance and thus portability comes from further and deeper understanding of the intent and the process and not just a simple 'almost the same'.

Look to CodeSys or a derivative of it for higher compliance.

 

Tim - isn't 'higher compliance' like being 'sorta pregnant'? you either are or you are not??

Cheers from: Jeremy Pollard, CET The Caring Canuckian! www[.]tsuonline.com

Control Design www[.]controldesignmag.com Manufacturing Automation www[.]automationmag.com

3 Red Pine Court, RR# 2 Shanty Bay, Ontario L0L 2L0 705.739.7155 Cell # 705.725.3579

 

Panel discussion at ISA in October... Info can be found here... IEC-6131 is really not a standard... come and have some fun!
- http://www.controlglobal.com/industrynews/2007/131.html