AB Compact Logix OPC tags Bad_Failure quality


OPC tags using the Ignition OPC UA AB driver (gateway v8.1.17) are all showing up with quality Bad_Failure. I cannot find a reason, if I go on the gateway in the quick client I can read and write tags without issues???



What is the firmware version of the PLC ? If v20.19 or higher, you MUST use the modern Logix driver. If firmware v20.13 or lower, use the legacy CompactLogix driver. (If 20.14-20.18, also use the legacy driver, but expect trouble. Consider flashing the firmware.)


I should have specified we are using the modern AB driver.

With which firmware? Why did you choose the modern driver?

It is version 32

Ok. Have you tried to subscribe in the quick client, too, or just read and write?

Will try that and post results.

{ Bedtime for me. Californians can take it from here… }


We are also getting spammed with these messages in gateway log. When we disable opc ua device they stop.

We can subscribe from quick client with no issues.

Consider restarting the OPC Server module itself.

Can we see the tag diagnostics for one of the bad tags and a screenshot of the Tag Group settings those tags belong to?

That you’re seeing those errors only when the device is enabled suggests you’re either using OPC Polled Mode, or you have periodic reads in a script set up, or transaction groups in Read Mode.

We have restarted the Ignition OPC UA Module with no change.

We were changing tag group settings to see if they were causing the issue, but nothing changed tags remained Bad_Failure quality.

Any reason you’re using polled instead of subscribe?

I think you may need to call into support to for some real troubleshooting, but as a last ditch effort I’d try installing the latest Logix driver module from the downloads page and see if anything changes.