GUI controls freeze frozen in a actor open-close-open scenario

[WolfiGeithner]

Hi experts,

I am a newbee to actor framework programming, but came quite far so far. Unfortunately, I have a problem I bang my head against without any success:

I have a step-motor control GUI comprising

• a starter VI pulling up
• the root actor (root actor core = UI allowing the user to select a step motor)
• child actor instances for the actual motor control
• child actor hosts up to three sub actors: one actor listening to a ZMQ message socket pushing measured motor positions to a shared variable (ZMQ requests are published from a Python program running on a RaspberryPi), one or two instances of a generic actor for controlling high voltages related to the detector setup mounted to the motor/linear actor (mechanical)

The whole  stack works as expected when I start it the first time: start starter VI -> start root actor -> start child motor control actor: child actor works, all controls are responsive, slider control showing the motor position with about 2 Hertz is jittering with incoming measurements via the shared variable.

However, after closing the motor control child actor using a button (and stopping up all the actors and queues, etc. This works all as expected) and re-starting the child actor, all controls on the GUI are frozen. Only the slider control showing the motor position is still jittering. When debugging, I see shared variable update events coming in as before.

The second round of opening can as well not be closed via the "stop" button. I can only use the "Abort" button, which leaves my chid actor instance in a locked state.

 

I checked many things (event inspector, LAVA task manager) none of them were conclusive.

And idea (as well how to investigate this further) welcome

Edited June 1, 2022 by WolfiGeithner
added screenshot for motor actor