possible to change opc ua alarm limits at runtime?

[smithed]

The answer appears to be no,  but I wanted to see if anyone had a solid answer. Is there any way to update an alarm limit at runtime using the 2017 opc ua library?

It isn't possible to add a new node while the server is running, which makes sense, but it seems like a pretty reasonable need to update an alarm limit while a system is operational and I can't find a way to do so.

[Jacobson-ni · Accepted solution]

I would add it to the idea exchange. I agree that it seems reasonable but I also don't know enough about OPC UA to really know if you are supposed to be able to do that.

I tried to find some way to do this using our API but I could not. I couldn't even find a way to truly edit the levels other than deleting the condition node and then adding a new condition with slightly altered values. Trying to do this when the server is running gives a pretty clear error that nodes cannot be added while the server is running so I can't imagine there is a way to get around that.

[smithed]

Ok thanks. Added here if anyone else wants to upvote it:

https://forums.ni.com/t5/LabVIEW-Idea-Exchange/allow-editing-of-opc-ua-alarm-limits-without-restarti...

[ThreeLions · Accepted solution]

Hi，

If you want to change alarm limits by the OPC UA server, the answer is yes. But you need to use the Write.vi instead of Add Condition.vi. As alarm limits are created into nodes, you can input values of nodes to change alarm limits.

Let's say the example VI, Limit Alarm Server.vi. If you want to change the value of the high high limit, you can input the Level Alarm Notifier.LevelAlarm.HighHighLimit to the node ID of the Write.vi. Then input the new value.

However, the value cannot be changed by the OPC UA client. Because the access level of alarm limits are read only.

Thanks!

[smithed]

I guess I missed the notification (or didn't get one) on the last post here, but thats great news. I'll give it a go.

Thanks