OMRON c200hx command : @cmp, need your help .

[machelec]

OMRON PLC C200HX or CS/CJ .
This PLC manual said that CMP(20) command don't support @CMP(20) type .
but I can use CXP3.0 edit @cmp(20) and transfer it to PLC .
PLC execute it normally.
Why ?
Is the manual wrong ?

Thank you .

 

[ArikBY]

The @ before the command mean that the command will work in one shot.
(raise on)
You should see after you transfer it to your PLC if it work that way.
My guess it will work.
I dont see any reason why it work with other PLCs and not with C200HX.

 

[machelec]

Thanks for reply .
I know what @ means .
the problem is why the manual have not mention : @CMP ?
It said that CMP only use to CMP type ,no @CMP type .

 

[ArikBY]

Did you tried if it work on your PLC?
Omron decomentaion is usually well edit.But maybe they have reason for that.I can not see any reason why not.

 

[Jay Anthony]

Omron official explanation:

Because of the nature of the common <,=,> flags, in certain situations, unexpected results could occur with the use of @CMP. Therefore to avoid these results we offer thwe folowing recommendations.

Recommendations:

1) Please do not use @CMP. Use only CMP.
2) If you use @CMP, please do not use @CMP after CMP.

Note for Equal flag 25506:
When MOV #0000 Source chanel is executed, this flag turns on. Equal flag of the ladder turns on, therefore, we have to inhibit the output of CMP, when condition is turned on at the moment. The combination and order of ladder program is to be also taken care by knowing the behavior of the flag.

 

[ArikBY]

Jay

What is the different between CJ1 to CQM1H in this case.
This recommendation is also for CQM1H?
Could you please wide about 25506

 

[Jay Anthony]

What is the different between CJ1 to CQM1H in this case.

CV, CS1 and CJ1 handle the @CMP correctly as expected.
C Series (CQM1H, C200HX, CPM, etc. do not handle the @CMP correctly if they immediately follow a CMP.

Could you please wide about 25506?

25506 or the Equal Flag in C-Series PLCs is affected by many instructions. Basically when the result word of an instruction becomes #0000, the equal flag (25506) will turn on.

 

[machelec]

Jay
Thank you very much !