BobB

Modbus SCU Function block

7 posts in this topic

Has anyone used the Modbus RTU for SCU function block from Omron France at all?

I have written a heap of code and getting done bits back and moving on to the next read fine but there is no data coming back.

I have uploaded the function block here as well.

I have not uploaded the code at the moment - there is a hell of a lot of it.

The processor is a CJ2M-CPU35 - big boy. Ran out of memory with a lesser processor.

May have to go back to the PMCR system if no one can help.

 

MRTU_SCU_Master.zip

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Here is a section of the program I have written.

The done bit is used as a differentiated contact to operate the step flag.

That all works but no data coming back at all.

No errors either.

hopefully someone can help. I do not often get stuck over a problem - stuck this time.

Modbus RTU Problem.cxp

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Hi Bob,

You are calling 40 instances of the FB each scan. The limit for this block is 32. Have you tried to run just a single instance to see if you get a reply?

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Hi Chelton - will give it a go - I did not think the quantity would matter as I am using the done bit but nothing is coming back so do not know why the done bit is turning on.

This lot is power monitors - I have another lot for AOP sterilisers and another lot for VSDs.

All on their own serial ports but there are quite a few reads from the drives as well.

 

I just put a set bit in and then a .2 timer in front of the read bit and the timer also reset the bit. Slowed things down - no result either. Puzzled. Back to PMCR I think.

Edited by BobB

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Did you set up your SCU as per the documentation?

6141887d33137_ScreenShot2021-09-15at3.47

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Did not set the timeout - everything else is correct.

Did not think timeout would matter - will give it a go.

Otherwise back to PMCR - pressure on of course and no time to fiddle.

Thanks for looking and helping.

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Time out addition did not help - still no response.

Back to PMCR - have to get it done.

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