PLC Programming Archive

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Thread Starter

Chuck Meyers

Does anyone know of any PLC (Ladder Logic) program archives on the Net?

I am always looking for new ways of solving old problems, Better tuning of PID loops, More efficent program control, different ways of machine control.
 
K
If there's a need for an archive of PLC programming solutions we'd be glad to provide the site for one (subject to pertinent disclaimers <grin>). Any interest? Any contributors?

Ken Crater, President
Control.com Inc.
[email protected]
 
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Chuck Meyers

I could always find some usefull code lying around (if there aren't any copyright isues <GRIN>).

I hope that others would also help. I can't believe that it hasn't been done yet!
 
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I think it's a good idea, and I'd be willing to put some time into it (if only because there ISN'T anything like that out there so far as I've seen), but what format? Deciphering symbols done in straight ASCII (i.e. - |/|, |Tmr|, etc.) turns to gobbeldygook for more than a line or so, and so far as I know there isn't a 'standard' cobbled together ASCII notation in force.

Could do it using a boolean notation, but that would leave out the folks unfamiliar with this format, and again, whose convention to use for
branching commands, timers, and the like (GE, A-B, Omron, etc.)?

It would be interesting to do some of the 'classics' in Rosetta Stone fashion. One of the best MS-DOS computer programming manuals I have (or had, can't find it now that I want the title) explained various bread n' butter tasks like disk I/O, etc. using assembler (direct to the hardware, and through BIOS calls), and using BASIC. This cleared up a lot of questions.
Maybe the PLC equivalent would be to have the 'standards' (say, a motor starter control) shown in a half dozen or so PLC manufacturer's ladder and boolean (where applicable) representations, IEC structured format, etc.
 
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Scott Jensen

Hey Chuck,
If there were such a ladder archive site, I would be happy to donate numerous programs to it. I think it is a fantastic idea and a way for people to share their programming styles. If no one knows of a site, lets talk control.com into helping us!
Scott Jensen
[email protected]
"The Lightning Man"
 
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Michael Griffin

Sounds like a good idea. I would be willing to contribute some subroutines I have written and found useful. I have a few suggestions though.

1) Contributions can be complete programs, or individual subroutines or code fragments. Small subroutines or code fragments will probably in most cases be more useful than entire programs. Complete programs can sometimes
be useful though in order to illustrate an overall method of organisation, or to show the context in which certain subroutines are used.
2) The contributor should be the author of the code. No sample should be accepted unless the contributor is willing to state that he wrote it.
3) There should be some way of associating additional documentation
or explanations with the program.
4) Submissions should include a descriptive title and a brief summary explanation which would be used by someone else to search or browse for something.
5) It would be nice to have some way of displaying a "print-out" form of the program, so that it can be viewed without using the intended
programming software. This would be especially useful if you find a sample which does something you need, but need to translate it to a different brand of PLC before you can use it. Some programming packages support a "print to disk" function which can be turned into a simple ASCII file which can be viewed directly. In other cases, you might need to use something like
"Ghostscript". Small subroutines or code fragments might perhaps be sent in scanned as JPEGs if no other means is available.
6) It would be nice to have some way of allowing people to add their comments or reviews in some fashion (as in "tried it and it worked great", or "won't work properly because of ...").
7) Some sort of download counters would be nice for each sample. This would let people easily see which ones were the most popular. This
might be a crude indicator of quality, especially if used with item #6 mentioned above.
8) Some general guide lines for submissions should be issued before the archive is activated. Some sort of classification scheme should also be instituted (e.g. "bar code reader interface subroutines", etc.).
9) Programs of other types than just PLCs should also be accepted (servo drives, MMI panels, etc.).
10) The archive should have a summary on the entry screen showing when it was last updated so someone can see if anything new has come in
since the last time they looked.
11) Each entry should be date stamped with the submission date.

**********************
Michael Griffin
London, Ont. Canada
[email protected]
**********************
 
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Chuck Meyers

Sounds like a webmaster to me! Are you volunteering?

All of your suggestions sound great but would require a full time person(s) to accomplish such a task.

I personally would like to see "concepts", not necessarily full Ladder Programs. I think that there would be less of an issue about Copyrights if concepts, code 'snippets', or ideas were submitted vice fully working progams. But I'm an engineer, not a lawyer (thank God!)

----

I personally don't like the idea of submitting code for specific PLC platforms. I currently program with 3 different PLC manufactures with multiple platforms. But I can see someone submitting the exact code that I looking for, for a platform that I don't have software for, or the currect version of software. That would create a ton of messages, "Can some convert XYZ to ABC?"

---

Anyone have a program that could display some form of texted based Ladder? I have seen examples in books and documentation in 'text' form.

I suppose I had better get back to "The 'Ol Salt Mines."


Chuck Meyers
Electrcial Design Engineer
[email protected]
http://www.grotecompany.com
 
I believe the archive would be useless as programming codes and PLC modules are constantly updated and improved. Plus each manufacturer has different scan times, module performances, and rack configuration rules. Would you want a program designed with an older PLC and different modules used on a completely different application?

I have heard that GE Fanuc has a product called FX Manager which would allow you to keep a central archive within your own facility. This program can do things like provide audit trails of people who have checked out the program,
schedule downloads from a central server, and do comparisons of programs. You can contact GE at www.GEFanuc.com
 
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Ken,

I think this is a good idea. I have created some common code that I use for certain functions for our company. I think if anyone wants to share this type of code that it would be great to be able to find reusable code on the web. Tell us where to stick it! hahah

Dale
 
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Daniel Boudreault

Sounds Great!

How can we do it, so that everyone without the programming software can view the code?

I know that I have some sample programs when I first started PLC programming, just to learn how each instruction worked.

It would be nice to see a tutorial section, which includes plc instructions from various manufacturers.

Dan B.
 
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Bob,

Why not store it in original format so it can be directly used by the software for the particular type of machine? It would make the
archive larger, but easier to use. Notation from one type controller can not usually be imported directly from different manufacturers or even different platforms from the same manufacturers. Most PLCs have the ability to save portions of the program as files to be used in other projects anyway, just use the native file types.

Dale
 
Excellent suggestions from Michael Griffin, I would contribute to such an archive as well. Another suggestion would be to structure the archive database by PLC manufacturers ---> PLC Model ----> Full Code ----> Subroutines...etc.

Thanks
 
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Rob Entzinger Schneider Automation

I got a few questions/suggestions (some may have been asked before)

1. How does one store the files?:- one config,source and comment could be many files
2. How could one look at the code? if you don't have the programming s/w. (May the app is on AB and I want to Modicon)
3. Why not standardise on IEC 61131-3 format?. (look at http://www.plcopen.org for compliance etc.)
Then (in theory) any IEC compliant s/w can be look at by any other IEC package.
4. When exported to text, the IEC code can be looked at in notepad. (one file, but difficult to read)
5. Else you could goto http://www.modicon.com/ConceptDemo/index.html to
get a demo package that could view and import the ascii IEC text file.
6. Saving this file in the arcive would then imply "open" by default

Rob
 
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Michael Griffin

At 15:01 01/06/00 -0400, Chuck Meyers wrote:
<clip>
>All of your suggestions sound great but would require a full time
>person(s) to accomplish such a task.

No, I don't believe it will. I think most of the suggestions were made with keeping administration to a minimum. The big question is whether some of the "nice" things like "down load counters" can be implemented easily and cheaply.
Perhaps the e-mail archive system could be used somehow, with new topics used to classify the submissions.

>I personally would like to see "concepts", not necessarily full
>Ladder Programs. I think that there would be less of an issue
>about Copyrights if concepts, code 'snippets', or ideas were
>submitted vice fully working programs. But I'm an engineer, not a
>lawyer (thank God!)

I think that subroutines or code fragments would be what most people would be looking for. The exception would be if they wanted to see how an entire system went together. That is, someone had a complete "system" or
"method" they used, and needed an entire program to illustrate it.
As for copyright issues, even if that were not a concern, some people might be upset to see someone else submit their work.

>I personally don't like the idea of submitting code for specific PLC
>platforms. I currently program with 3 different PLC manufactures
>with multiple platforms. But I can see someone submitting the
>exact code that I looking for, for a platform that I don't have
>software for, or the currect version of software. That would create a
>ton of messages, "Can some convert XYZ to ABC?"

I scanned various ladder format subroutines and code fragments into JPEG files to illustrate examples in a programming guidelines document recently. These subroutines and code fragments varied from 12k to 90k in JPEG format. I didn't spend a lot of time trying to minimise the file size, but they were still fairly compact.
Something that was in instruction list format could of course be a simple ASCII file. I agree though that we should encourage people to send stuff in universally accessable formats. Some stuff could be constructed manually as ASCII characters - this isn't always easy though (we've seen examples on this list).

I don't suppose though that anyone has heard of web browser plug ins to view PLC programs though?


**********************
Michael Griffin
London, Ont. Canada
[email protected]
**********************
 
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Dale,

That would certainly make submissions easier, and would be a necessary adjunct of any scheme, but (until the ladder logic programs start to support some manner of 'export to HTML' ) would make it impossible to see the contribution online.

What I see is a viewable HTML page showing familiar, pictographic ladder logic, an I/O table showing the devices, etc. a synopsis of what the code does, a link to a more detailed analysis/commentary if warranted, and ftp links to download the code in one or more native PLC formats.

Maybe if I get time over the weekend I'll play around with RSL500, and see if I can't cobble together a demo page on my home page, and then list the URL here for comments.
 
K
Some great ideas have been presented for the archive -- we've also had someone volunteer to maintain it, and have started a side discussion about how things might work.

We've just registered a new domain "plcarchive.com", and are starting to
plan the site now. A remaining question, that several people have already mentioned, is how to best represent programming concepts so that people
using a variety of equipment types can make use of them. A pictorial representation, as mentioned by Michael Griffin, would probably be best, along with commentary and provision for subsequent discussion.

Our existing web tools make it easy to allow discussion threads associated with any given posting. The question, though, is how to convert ladder diagrams from a large number of different vendors' programming software to a common graphical format that can be presented on the web. Is there anything better than ASCII art for this purpose?

Ken Crater
Control.com Inc.
[email protected]
 
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Dale,

... or maybe not wait 'til the weekend ... was tapping my toes waiting for a big PDF to download, so jumped in to see what could be done in 20 minutes or so.

http://www.ccomm.com/~users/rawelk/techteach/plc/plc_code_snippet__test_page_.htm

Drop in on this page. Actually, I was kind of suprised how easy it was to do something rough (which is all I'm capable of doing at this point; need to learn how to get around various scripting languages, Java, et al), but still almost worthwhile.

Bob
 
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Mark Liszewski

> 1. How does one store the files?:- one config,source and
> comment could be
> many files

AB for example uses 1 file, unless you save it in the old format. Modicon & GE will hopefully get with the game and implement something similar.
Typically, there is no need to have 20 or more files for a project.

> 2. How could one look at the code? if you don't have the
> programming s/w.
> (May the app
> is on AB and I want to Modicon)

Still beneficial to us that have most of the programming packages.

Since we are talking mainly about sample routines or snivets of code, why not just do a screen capture and save/display in a graphic format...bitmap, WMF, GIF, etc. This would provide enough insight into what the original
author had intended to show.

As far as compatibility between different manufacturers.....who cares, enter the logic as shown or modify it slightly to the platform you want to run it on. There really isn't that much difference. The whole point is to provide a working example or solution to some problem.

Personally, I think this is a great idea.

Mark Liszewski
ZTR Control Systems
 
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Mark Liszewski

> The question, though, is how to
> convert ladder
> diagrams from a large number of different vendors'
> programming software to a
> common graphical format that can be presented on the web. Is
> there anything
> better than ASCII art for this purpose?

If the ladder logic/program isn't too large, use screen capture or print and then scan, and save in graphical format....jpg, bitmap, WMF, etc.

Mark Liszewski
ZTR Control Systems
 
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Bruce Durdle

1. Base it on the IEC ladder/block formats

2. How about Word line drawings - can it be done with text boxes?

3. Basic ladders are no problem with multi-vendor formats - but there are major differences between eg Modicon timers and those for other vendors and the same applies for other complex functions.
These family differences will have to be maintained.

Bruce.
 
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