I am also the owner of several Idiom Press RotorEZ Yaesu and Hygain versions. I also have had lockup problems. Maybe excerpts from my comments to Idiom Press may offer ideas for those who have already invested and built these into your controllers.
++++
Idiom Press:
Hi, I am the owner of several RotorEZ units for both Hygain and Yaesu controllers. It is a well known that the communications may appear to lockup or quit for whatever reason. This is awful for remote operation. It would be good for newer versions to recognize a lockup and restart but that would require some coding and would not correct the many now in use.
.....
In my experimentation with local com ports and remote serial over ip ports, either or both, RTS and DTR are invoked when the port is accessed. DTR is almost always active when the port is active for rotor control and quickly shuts off when the port is inactive. This could be used to reset/power the processor on every remote access. It could also be used to switch the mains power through a relay. Power savings being a side benefit.
...An optical coupler could be used to reset the processor but it would probably be easier to just interrupt the DC supply. If there is no remote operation everything will still work locally.
...You can use a solid state optical switch*.
Best regards,
John Spigel, W1AN
++++
*Note: DTR from DB9 pin 4 through a 1K resistor, optical switch and LED to pin 5 ground. Switch needs to handle the max DC current needed for the RotorEZ. Consider using a Toshiba TLP227G for the Yaesu DXA version but current needs to be measured for others.