Modbus TCP Device Issue

Hi Guys,

I connected a Comet P8641 (Modbus TCP 4 channel temperature monitoring unit) to my desktop PC on a local network and was able to add the device to a trial version of Ignition I have running on my desktop.

I then added all the tags and was getting values.

I then disconnected it from my local network, connected it to our automation network (which has a bunch of Modbus TCP devices communicating happily through port 502), added it to our gateway (status says connected and I can ping it) and copied and pasted all the tags from my local Ignition to our corporate one.

Unfortunately all the tags’ quality is ‘Uncertain_InitialValue’…

Any ideas?

My colleague took a look and instead of adding tags via the designer tag browser he added a tag to the OPC Server via the gateway → OPC UA → Device Connections → {Device} → More → Addresses

Not working tag (added through designer tag browser):

Working tag:

As you can see they are configured identically.

I believe he has discovered a bug and a work around - just thought I would share.

The OPC Server name is different.

Ahhhhh! Thanks Kevin!

In a recent version we cleaned up the error diagnostics on tags that have an incorrect OPC server name:


Hopefully this helps people out in the future.