Citect and remote Modbus device

[savery]

Hi all,

I have an issue which is frustrating me no end, and I am sure its something simple I have missed.

We have Vijeo Citect 7.4, and I am trying to incorporate some of our remote sites into it. We have a pump controlled by a Unitronics V200, that is causing me grief. It is a remote site, and behind a Comset M2M router. It has ports 502 and 20256 forwarded to the PLC.

I can connect to the PLC over the internet using Modscan, and I can poll it and see the values I want to display. I have the Unitronics app on my phone and I can turn the pump on and off remotely. So, I am confident that it’s not a network issue.

My problem is when I try and configure it in Citect.

I used the express communication wizard to create the IO device (External I/O -> Modbus TCP, then created a Variable tag, and then put that tag on a display, everything compiles fine.

I am constantly getting #COM (Bad) error. I have been pouring over the documentation, tutorials and guides I can find and I am sure I have configured it correctly, but equally sure I a made an error somewhere

Can anyone offer any insight to where I might have gone wrong?

Thanks