How does the listener works? @Question

[JohnLeBuff]

Hello,
I have a question that I did not find in the documentation.
The OPCUA Listener Node, how does it work?

Does the listener request data from the server or is the listener a subscription to the “nodes”?

Because I use the injection node to inject many OPCUA variables that I want to retrieve and process in Nodered. Some of these variables are not updated if the state change is only for a short period of time e.g. 1.5 seconds.

Hope someone can help me and thanks
John

[mikakaraila]

Subscription contains also sampling interval (100ms fastest) and publish is normally 1000ms.

This should work in your case.

[JohnLeBuff]

Hi, thanks for letting me know.

Im still facing an issue, maybe u can help me or youve heard of something similar. Basically we have an SPS acting as an opcua server and a raspberry acting as a client using node red. Now I want to publish sensor values to the raspberry. This works quite well and we get every state of the sensor.

After a while this method seems to run into trouble. Every now and then we get 3 seconds where we get no data. It feels like a timeout. But the node does not disconnect, it still maintains the "listening" state.

Problem is, if the timing is bad, we miss a sensor state which results in a problem. Have you heard of anything similar, or do you have any idea how to prevent such a timeout?

Maybe im missing something in the best practice because i only have one listener for 30 opcua variables. im not sure if its better to have multiple listeners or maybe even one listener node for each variable.