Modicon Quantum PLC instruction questions

[VSandhu]

Hello All,
Was hoping I could get a little help with Modicon ladder logic. This is the first time I have seen Modicon logic and currently trying to convert to Rockwell. Any assistance would be greatly appreciated.
1. In the logic below does the vertical short passing through the horizontal short (highlighted) tie the two rungs together? In other words either contact left of the short can pass power between the two rungs?

2. With the SUB instructions placed side by side does that tie all three outputs from the SUB on column 3 to the input side of the SUB on column 4? If so, is this a way to create a limit instruction where if the data in 41001 is between 25 to 33 power is passed through?

 

[bb76]

1. Yes, either contact will activate all branches.
2. The lower right pin of the sub box will be true if Value 2 (middle) is greater than value 1 (top). So the first box pin will be true if CIP step number is greater than 24 and so on.

 

[VSandhu]

Thanks for the reply bb76. For the first lower sub instruction does all 3 of its output pins connect to the next sub instruction? When you place them side by side it appears that all 3 output pins from “automatically” attach to the next sub. How to tell which output is being used?

 

[Lare]

Thanks for the reply bb76. For the first lower sub instruction does all 3 of its output pins connect to the next sub instruction? When you place them side by side it appears that all 3 output pins from “automatically” attach to the next sub. How to tell which output is being used?

it works also as compare block

Top:
val 1 > val 2
Middle:
val 1 = val 2
Bottom:
val 1 < val 2

As all outputs are connected, I assume that first comparing probaly does nothing.

p.s You can download Scheider Control expert and code and simulate there 984 ladder still. If you have old lmodsoft or Proworx files then you should able to open files on Control expert. L984 needed seperate selection for enabling.
Control expert works 21 or 30 days without license.

 

[VSandhu]

Lare, thanks for the reply. Ok that makes sense, I was thinking it has to be all connected and being used as a compare. The instruction manual does not explain (at least that I found) that this sub can be done like this. It states that the sub only has one top input. That made me double think should there be a visible horizontal short from each output to the top.

Thanks for the simulate tip. That will come in handy.

 

[Lare]

Lare, thanks for the reply. Ok that makes sense, I was thinking it has to be all connected and being used as a compare. The instruction manual does not explain (at least that I found) that this sub can be done like this. It states that the sub only has one top input. That made me double think should there be a visible horizontal short from each output to the top.

Thanks for the simulate tip. That will come in handy.

It can be also graphical "show error", and on reality sub has one input. But with three outputs it looks like they all all connected when another block is side to side.
If there would be space between blocks, then it probably would show that top pin is actually connected and there isn't other inputs on sub block.
So it would be compare if >29 for another blocks input.
Old modsoft PLCs used little bit more programming memory if there was unnecessary lines between objects. They were sometimes optimized by programmer. Also space on rung wasn't wide either.
Hopefully there isn't much extended floating point math as they are sometimes confusing without real PLC and values.
(ex. You read extended math result from different memory address than where you point math result. (Mul, Div).
Long time allready when have readed modsoft code

 

[Lare]

p.s Lmodsoft have normal math and enhanced.

Div and multiple uses two memory addresses for result (low 0.9999 and high 0....9999) and that is why you need to look diffrent address for reading and pointing values.
Enchanded math need different amounts memory on different calculations and you need to look from manual what EMTH block does with different numbers.