Hi, short answer: QuickOPC-UA currently does nothing like QuickOPC "Classic" does in terms of setting up automatic subscriptions that match the Reads. But there are other things going on.
Longer answer:
QuickOPC-UA does not set up subscriptions to monitored items that you Read or Write.
There are, however, 3 other mechanisms that you may notice when analyzing the communication:
1. Shortly upon a connection, there are some Reads made from pre-defined nodes. They appear just once, and are made by the OPC UA .NET stack for us. They are more or less mandated by the OPC UA specs, for things like the server's namespace table - a pure necessity. Cannot be turned off.
2. The OPC UA .NET Stack issues a periodic "keep-alive" Read: I think it is reading the server's Status. Cannot be completely turned off, but the rate can be influenced by some settings that we expose (and is revised by the server itself, too).
3. On each session, we create a single additional subscription with monitored item(s) that also watch things related to server status. This has been added because of OPC compliance requirement. Currently it probably more or less duplicates the functionality under #2, but it is possible that in the future we will add more monitored items to this subscription. The items are all well-known, pre-defined pieces of information within the OPC UA server, they have nothing to do with what the developer actually later subscribes to. And, the default rate is quite slow (I think 15000 milliseconds for the sampling rate, 7500 milliseconds for the publishing rate). We expose settings that allow you to change the rate; you can even set the rate to Infinite in which case the subscription won't be created at all.
I am not aware that any of these mechanisms would be causing issues/problems.
Best regards
