Hello,
I am working with an ABB system and all the PID loops have 4 tuning
parameters: overall gain, Kp, Ki, and Kd. No units are given for Kp
and K, but Ki units are shown as 1/minutes and Kd as minutes.
Theoretically I understand how these controllers work. In fact, I
probably have way more education than I need, and I might be making
this more difficult than it needs to be. But I don't understand the
units. I see the 4 K's as gains. Here is my take on it. Please tell
me where I have gone wrong:

The gain simply multiplies the error by Kp. So the Kp contribution to the controller output is Kp

So, the question is (if I even have one), is how do I relate Ki and Kd to units of time? Do these values scale the error, or do they determine the sample rate for integral and derivative?

Thanks for your help.

The gain simply multiplies the error by Kp. So the Kp contribution to the controller output is Kp

***error. The integral portion sums a scaled version of the error on every sample. So the contribution of the integral is Ki***(sum of errors). And the derivative contribution is Kd* (rate of change of error).So, the question is (if I even have one), is how do I relate Ki and Kd to units of time? Do these values scale the error, or do they determine the sample rate for integral and derivative?

Thanks for your help.