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.
I've wanted to do something like that for a while anyway to set different PID tuning on startup to get up to temp faster then switch over to settings for stability and maybe do an auto-off timer. A lot of industrial stuff is simple enough and uses stuff that's sufficiently standardized that these sorts of things can be hacked together pretty easily.
Probably won't be able to get to it until after the start of the year.