I wrote something years ago for my MS to convert ladder
diagrams to HLL source code. The output is generated using
templates, so you should be able to make it output structured
text. The ladder diagram editor is in Scheme and the code
generator is in C. You're welcome to use it if you like:
Grant Edwards grante Yow! I want EARS! I
at want two ROUND BLACK
I have an existing ladder diagram that I want to convert to Structured
Text. I don't want to re-write the whole ladder-diagram in another
program. I wrote the ladder diagram in Allen Bradley RSLogix5000.
The point was not that the program would work for you as is, but that you could
modify it to produce blocks of ST in response to each ladder element instead of
producing blocks of code in response to each ladder element.
If you're not comfortable programming, consider hiring a programmer to make the
tool do what you want it to do.
Check out Mathcad explorer. Although mathsoft stopped providing this,
one could always easily find copies floating around the net!
That brings the problem back to where it started... How to convert the
existing ladder diagram into 'something else' (Structured Text or C)
I want to run the PLC-code on a PC, so I have to translate the
PLC-code (ladder diagram) to something that can be compiled on the PC
(C or basic). And the program has to be exactly the same, so I don't
want to rewrite the program in C, but I want to convert it with a
Maaike (is a 'she', not a 'he' :))
firstname.lastname@example.org (Sunny) wrote in message
I had a similar situation with an old OMRON PLC program, but never
found a "convertor", so I just re-wrote the program. Please post if
you do find such a "convertor".
You mention above you need a "convertor" because you intend to run
your PLC-code on a PC. If your open to other methods besides C or
basic, then you may be interested in products similar to those offered
at www.softplc.com, which basically emulate a PLC via software on a
I've been pleased to find that some newer PLC programming software
includes conversion ability between different IEC 1131-3 programming
languages (structured list, ladder, function block).
Sort of. It brings the problem to "how to get a net-list" of
the ladder diagram. A net-list is logically the same as a
ladder diagram, but the chances are probably slim that your
existing toolset can save the ladder diagram in a net-list
format that could be easily converted to the form expected by
the code generator I wrote.
 A net-list contains only the information on connections
between objects in the ladder diagram and doesn't contain
any "graphical" info on where objects were located on the
And you don't want to re-draw the ladder diagram either...
Sorry about that. One sometimes wishes that English had a
formal gender-neutral third person pronoun that one could use
when speaking of somebody with whom one is not familiar.
Grant Edwards grante Yow! .. the HIGHWAY is
at made out of LIME JELLO and
I guess it all depends on the programming software you used to build the
ladder. If you developed the ladder program in anything but an IEC61131-3
environment then you're probably out of luck.
If you used a true IEC61131-3 package, you should be able to save the ladder
as a FB, then import that FB as IL/LD/ST..etc.
I you used a non 1131-3, like RS Logix, then I know of now way to do what
I build it in RSLogix5000. And the help-file of RSLogix5000 says:
"The RSLogix 5000 Enterprise Series environment offers an easy-to-use,
IEC61131-3 compliant interface"
But I don't know how to save the ladder as a FB. Maybe anybody can
help me with that?
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