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I am new at ladder/grafcet programming for PLC's.

I have a Windows application of my own that will write on a OMRON PLC memory (D register). The idea is to fill blocks of memory that will trigger some output (ladder programming).

So imagine for example a memory block of 5 words (D0000 to D0004). The outputs will be trigger by the contents of this 5 words.

My idea is to have one simple ladder program to "run" block of memory. So each 5 memory blocks will contain "instructions" to activate my outputs.

I tough : maybe I can implement like a "program counter" concept where the program counter points to the first 5 words and co+y/move its content to a general location on memory that will trigger the contracts of the ladder program. Then after the execution of the first 5 words the program counter will point to the next 5 words block to copy it content again and the ladder program execute its "instructions" and keep this for undefined number of 5 words block.

I am not sure if I was able to clarify my idea. There is a way to implement this using PLC ladder logic ?

Or there is any other ways to implement such thing ?

Keep in mind the idea is to have blocks of memory (composed by a fixed number of words) and each memory block will have on its bit the necessary configuration to trigger the necessary outputs (using the same ladder diagram/program).

Any help or better ideas will much appreciated. Thank you very much

This is to use with a OMRON C2JM PLC.

Dimitri9494
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  • Thе task like this would be resolved much better in ST. Does OMRON support ST language? – Sergey Romanov Jun 19 '19 at 05:17
  • @SergeyRomanov I didn't know the answer to that question, but I googled it and omron does support ST language. So the idea should be make a "ST small program" to made this job and call it inside the ladder program ? – Dimitri9494 Jun 19 '19 at 20:26
  • If you use ST or maybe even in ladder you can access individual bit in DWORD like myvar.0. You can read it and set it this way. – Sergey Romanov Jun 21 '19 at 04:59

1 Answers1

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You're thinking too hard about this. A PLC is a state machine, not a procedural processor. Just route the bits directly to the outputs they need to control.

For example, bit 0 of D1234 should control CIO output 1.00 then 

 D1234.00                     1.00
----| |------------------------()

and if D1234 bit 12 should control CIO 2.15

 D1234.12                     2.15
----| |------------------------()

etc.

J...
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