Help sending Modbus ASCII command by serial gateway

[PdL]

I am trying to replicate a Modbus ASCII command I can send through my Modbus simulator with the CMND function block. My setup: CJ2M CPU 34 with SCU41-V1 v1.3 unit #0. I have setup the SCU port 2 to User settings, Serial gateway, 9600, 1 stopbit no parity. According to the function block PDF I think I have setup the parameters correctly, and if I monitor the command word data it also looks ok. Not sure if I have the no. of bytes parameters setup correctly, I was not sure if I should also include the FINS header and command. All I get is error 0401: Command not supported... Any suggestions / help welcome! Modbus ASCII by CMND instruction.pdf _CPU012_SendCommand.pdf

[Jay Anthony]

Serial Gateway only passes Modbus commands from one serial port to another serial port transparently. You cannot originate a Modbus CMND from a PLC memory map. PMCR should be able to help you with this.

[PdL]

Hi Jay, I know questioning you is like doubting the earth is round, but are you sure? Because I turned to our Omron distributor to ask if they had a Procotol Macro for Modbus ASCII and they suggested I would use CMND for this. And if I read this from manual W336, it looks like the Modbus command is originated from the PLC...

[Jay Anthony]

I concede. Need to catch up on my manual reading. Send a private message to PMCR. I'm sure he can help you out.

[PdL]

Yeah, I will raise him a flag, thanks

[PdL]

I got a call from my Omron helpdesk, and apparantly I have set the SCU unit identifier incorrect, they could confirm it should work when this is set correctly. I will test again net week and post my findings!

[PMCR]

When sending a FINS command to a specific port on an SCU card, you use the following formula for the 'Unit' destination. Port 1: 128 + (4 * SCU Unit dial) Port 2: 129 + (4 * SCU Unit dial).

[PdL]

Thanks PMCR, after changing the SCU unit/port identifier it works like a charm!