Stale Tags

I have several tags that go from good to stale for no reason. Looks like this is a common problem. I am running the the versions listed below.

Ignition Platform
7.2.9 (b200)

SQL Bridge Module
5.2.6 (b34)
Vision Module
4.2.7 (b106)
Mobile Module
1.2.6 (b36)
Reporting Module
1.2.6 (b26)

What devices are the tags from?

How are the devices performing? To find out, login to the Ignition Gateway configuration section and select OPC-UA > Devices. Click on the diagnostics link to the right of your device and post the information to the forum.

Lastly, if you have any error messages in the Console of the config section post those as well.

I didnt see any error messages.

Request Schedule
SubscriptionItem Count 1183
ScheduledRequest Count 87
RefreshRequest Cycle
Request Throughput 17.9/sec
Min Request Duration 0.0ms
Max Request Duration 14844.0ms
Avg Request Duration 52.3ms
Last Request Duration 66.0ms
Request Count 87
Request Throughput 17.5/sec
Min Request Duration 2499.0ms
Max Request Duration 6132.0ms
Avg Request Duration 4813.7ms
Last Request Duration 4825.0ms
Avg Wire Time 52.3ms
Avg Queue Time 4758.9ms

Your average request duration for the 1000ms rate is really high, almost 5 seconds. There is a setting in Ignition under OPC-UA settings called State Threshold (in the Ignition Gateway config). The value is set to 5 by default. That means if your values don’t come in from the PLC within:

1000ms x 5 = 5000ms or 5 seconds

the tags can become stale briefly. If the device is a ControlLogix I would recommend increasing the number of concurrent requests to a higher number. If not, you may need to figure out why there is a big latency. If all else fails you can just increase the stale threshold to 7 to give yourself more time.

The device is a PLC5-80. We never noticed it with FactoryPMI. I changed the stale threshold and we havent notticed it yet.