I have wired up an ITC-106VH using a K-type thermocouple and an SSR to control the temperature of a toaster oven, with the goal of maintaining Sv=400F at +/-3F.
With the factory default settings for the P=50, I=30, and D=8 values, I see overshoots of Sv by +60F initially, and then settles at a 5.2 minute oscillation period of -7F to +34F from Sv.
Using the autotune methods yields nearly identical results.
Failing to perform properly either in factory default mode or autotune mode, I attempted various empirical manual tuning methods which I observed to have no appreciable effect different from my first attempts:
- Operate in P mode only, by setting I=9999 and D=0 and vary the P value looking for a stable Pv. When trying P between values of 1 and 5000, no significant changes in behavior were noted and the variance is similar to that of the factory default values:
- Operate PI mode, setting P=100 and changing I values. I tried many values if I between 375 with no difference. As a brand new user, I can only attach one media object, but the absence of any effect on the I value and the similarity of the Pv curves is unchanged from the P-only attempt at tuning.
One other thing of note: regardless of PID values, in every situation described above, the ITC-106 turns off the output exactly when the temperature rises through Pv=Sv, and turns the output back on exactly when falling through Pv=Sv…as if none of the proportional, integral, or derivative terms are having any impact at all on the system.
Do I have a defective ITC-106 or am I doing something wrong, because I’ve been testing this thing for three straight days and am getting close to getting rid of this PID controller.