PID Explained for Process Engineers: Part 2 – Tuning Coefficients

(Follow-up to "PID Explained for Process Engineers: Part 1 — The Basic Control Equation," CEP, Jan. 2016)

Control loops must be tuned to get the characteristics of the controller "in tune" with the characteristics of the process. The proportional, integral, and derivative modes each have a tuning coefficient, which must reflect the behavior of the process and the desired performance from the control loop. The objective of tuning is to obtain a value for each of the tuning coefficients.

• This article explains the tuning coefficients for each mode.

• Part 3 explains the most common controller features and options (March 2016 issue)