Subscribing to OPCUA nodes with a constant value

[KishanKishore]

When subscribing to a node with a constant value using asynua, there are no updates from the OPCUA server and the datachange_notification method is not repeatedly executed.

• Is this expected behavior ?
• Is it possible to make some changes on the client side so that the OPCUA server keeps sending notifications for such nodes with the same value?

[AndreasHeine]

https://reference.opcfoundation.org/v104/Core/docs/Part4/5.13.1/

why should data been send if it has not changed since last notification?

[KishanKishore]

@AndreasHeine Thanks for the quick response as always. I was actually going through the same page. Just need to confirm that this is expected behavior.

[AndreasHeine]

thats by the way the cool thing on subscriptions you get only datachanges ;)

[AndreasHeine]

if we would change it, it would be just cyclic polling.... a subscription is more like longpolling!

[KishanKishore]

It is confirmed here: https://reference.opcfoundation.org/v104/Core/docs/Part4/5.12.1/

Thanks for the help!