16 May 2011
Today I made a slight modification to the toaster oven to see if I can improve the PID loop response. I was having issues with oscillations no matter how much I adjusted the PID gains. I suspected this was because I turned the oven on/off in response to the PID output. This meant the internal oven fan pulled the temperature down below the setpoint a bit every time the oven was turned back on again. Another side affect is the temperature would overshoot the setpoint a bit once the PID attempted to compensate for the undershoot.