Omron FINS Driver & Tag Quality 'Uncertain_LastKnownValue'

Ignition
1

I've seen this issue randomly about 3 times while developing on customer's hardware (bench testing). This over the span of just over a year. It's never been reported by the customer in production. But I am curious.

In a vision client I see Unknown overlay on a PLC tag.

Typically, the PLC is not power cycled. The gateway PC is typically turned off nightly. In this last instance I turned off the gateway for few hours this morning.
Once back on, comms appear absolutely normal. But this one tag (so far as I am aware of there are no others).

image

If I restart the tag in the designer. It eventually goes away.
I am not sure why this happens, nor can I reproduce it.
Gateway is 8.1.36
Omron Driver 4.1.36

I looked at logs via the web admin.
Several "FinsTcpFrameCodec Exception caught, closing channel." are all that I saw in the time frame of interest. And the 2 that I saw do not speak to a FINS driver address (like many failed writes from when (I assume) I was doing something with the PLC).

Any insight would be appreciated.

2

We have had a similar occurence. In the log we got the same error message and after that we lost contact with the Omron PLC as it was constantly reconnecting. I did a change and revert on IP-adress in the settings and then it connected again. Did you ever find any reason for this?

3

If you find yourself in that situation again get a Wireshark capture if possible. Start it during the failed reconnect attempts, keep it capturing until after you do whatever fiddling with the settings to make it connect again.

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4

Sorry, I did not. End user has never queried me about any tag overlays so I assume on both production machines it has not occured.