Prior controller randomly locks up

[nicost]

We have a Prior XY and Z stage controller that at random moments stops responding through the serial port. The stage can still be moved with the joystick, but Micro-Manager commands time out. Functionality can be restored by power cycling the controller. Remarkably, Micro-manager does not need to be stopped and restarted for this to work. I suspect that multiple threads talking to the controller causes it to get confused, but I do not have an easy way to reproduce the issue.

[marktsuchida]

We have one Prior XYZ and haven't seen this AFAIK, but it'd be interesting to see the debug log.