Tuesday, 22 July 2008
Kiln controller now two-way, but eats relays
I've done some low duty cycle tests, and was able to fry my SSR (apparently, it needs a heat sink beyond 5-8amps), while I was also able to melt and/or boil off solider from the coil-relay replacement. That means it got to 400 degreesF at the contact point! Insane. I've tried beefing this up (more conductor should reduce resistance), but I've still had it fail. Might have to make a new board with large area for heat sinking. Or just wait for the replacement SSR to show up (which I will attach to an old CPU heatsink+fan).
The control software is coming along slowly. I'm probably going to make it more of a follow-the-curve sort of system instead of a true feedback or PID. Right now I'm doing everything I can to increase safety, like auto shutoffs and timeouts.
