Hello,
I am experiencing unexpected OPC UA subscription behavior in mappView.
I dynamically create subscriptions like this:
getValue() works reliably.
However, valueChanged() only fires if I additionally create a separate “test” subscription outside this logic, for example:
So, if this extra subscription is removed, no errors occur, PLC values change and valueChanged() callbacks inside my dynamic bindings never trigger.
And adding a single external subscription makes all dynamic subscriptions work.
Has anybody encountered or solved this kind of problem?
It raises some fundamental questions:
- is the OPC UA client or monitored item creation in mapp View lazily initialized?
- does getValue() guarantee monitored item creation, or does it only perform a read service call?
- is there a known timing dependency between page/session initialization and subscription activation?
- what is the officially recommended way to ensure reliable dynamic valueChanged() subscription setup during initialization?
The behavior suggests lazy activation or a timing dependency during initialization, but I would like confirmation whether this is expected behavior by design or an unintended issue.
I’m not sure whether this is an appropriate topic for the community, but I would appreciate any insights or experiences you can share.
Thank you.
Regards
Michal Malek
