Swapped out part of a heat sealer. Relay on the old controller was periodically failing closed which is the wrong failure mode. Thinking I might pop a Pi or similar with a relay hat and wire the RS485 pins on the controller to act as an extra safety monitor/shut down power to the controller in the event of PV exceeds SV by too much. There's room in the sealer and it's a relatively cheap mod for some extra safety.
Probably won't be able to get to it until after the start of the year.