It is an abrupt one. The script is running under CLI and I am using Ctrl+Break to stop it.

I have managed to get your example working in my test context and have expanded it to subscribe and handle multiple items so that only changed items are returned individually. It all seems to work well (after I upgraded the QuickOPC-COM software). I will now proceed to try to implement it in my real world context.In doing the work I have noticed behaviour that I had not expected, so I mention it here in case it is not intended. I am running EasyOPC-DA as a local server. If I call a SubscribeItem() with a RequestedUpdateRate of say 1000 then it updates at 1000ms as expected. If I then stop the script, and run it again with a RequestedUpdateRate of say 500 it updates at 500ms as expected. If I then stop the script and run it again with a RequestedUpdateRate reverted to 1000 it updates at 500ms NOT as expected. The update rate remains at the fastest rate defined.This is true until I stop the eopcdal.exe process. Once I have stopped the process and run the script again it then reverts to the 1000ms as expected.The behaviour wont impact my usage as the update rates will be constant, but it might impact others.