Siemens S7-1200 with Omron M1 - Modbus RTU

[KalvMavin]

Hi all,

Currently having trouble getting a speed reference to write over modbus to an Omron M1...

I can successfully write a run command and have confirmed the two devices are communicating.

I'm struggling with the documentation for the Omron M1, if I'm honest.

I've attached a snip of the MB_MASTER block I'm using for the run command. This is working well, however, being relatively unfamiliar with Modbus, I'm unsure what to enter in the block parameters to successfully write a speed reference to the drive.

I've also attached a snip of the M1 manual. I believe I should be writing to S05, to give the drive a run command, but unsure as it doesn't appear to have worked when I try.

Any help, much appreciated!

 

[KalvMavin]

Would I be correct in saying that the address I should be writing to is 45005? I've tried this, and no luck. I'm not sure if this is the correct address for what I'm trying to accomplish though...

 

[Steve Bailey]

Would I be correct in saying that the address I should be writing to is 45005?

Since the address of parameter S05 is in 5005h, the Modbus address for the parameter might be 420485.

 

[KalvMavin]

I’ve tried this, with no success, unfortunately.

I’m wondering if I’m writing to the wrong register all together…?

 

[Steve Bailey]

Have you checked parameter S05 to see if the value you are trying to write is getting received, or are you or is your concern based on the fact that the drive is not running at the speed you're trying to command?
Generally, there is a parameter in the drive that needs to be set to certain value to tell the drive which of several possible speed commands to use, for example, a 4 -20 mA signal at terminal X, or a 0 - 10 volt signal at terminal Y, or the speed command form the keypad, or the speed command over the network. This parameter is typically separate from the parameter that tells the drive to accept the run command from the network.
The above is based on my experience with drives in general, not with your specific model.

 

[Lare]

M1 manual gives modbus write example to C99 Frequence setting at address 1388h.
C99 is mentioned as frequence reference 1st
E109 is mentioned as requence reference 2st

Haven't used omron VFDs thought.

 

[KalvMavin]

Hi all,

Found the issue, thanks for your replies.

I was writing to S05 for some reason, when S01 should have been where I was writing to. Corrected this and all is working as it should be now.

Haven't used modbus for a while and was over-thinking the process I think.

Thanks again!