P
I've read in a few recent posts that the derivative term is extremely important for PID-controlled temperature loops. Why is this true specifically for temp loops? I know that in general (not only for temperature) an optimally tuned PID controller will perform better than a PI, but what makes temperature loops in particular so dependant on the D-term? In my case, I've done a lot of temperature loops with only P+I, and they work pretty well.
Perhaps in many of my cases a PID might have performed better, if I had spent the time and/or had the means to perform the open or closed loop tests required to fine tune a PID with Ziegler-Nichols, IAE, ITAE or whichever criterion available. In my case, I prefer not to mess with the D-term (except maybe through formulas when I have the 1st order process model), maybe because I don't have the "feel" with it as I have with the P or I terms.
In summary, in which particular type of temperature loops is the D-term very important?
Regards,
Pat
Perhaps in many of my cases a PID might have performed better, if I had spent the time and/or had the means to perform the open or closed loop tests required to fine tune a PID with Ziegler-Nichols, IAE, ITAE or whichever criterion available. In my case, I prefer not to mess with the D-term (except maybe through formulas when I have the 1st order process model), maybe because I don't have the "feel" with it as I have with the P or I terms.
In summary, in which particular type of temperature loops is the D-term very important?
Regards,
Pat