A PID tuned for maximum disturbance rejection in a composition, temperature, and gas pressure loop will exhibit excessive overshoot in the setpoint response unless one of several PID features is used. The options are relatively easy to configure. Here we discuss performance metrics and test results.
The performance criteria primarily used in control theory text books is integrated absolute error (IAE) for a step disturbance. The IAE performance criteria can translate to the total amount of material not at setpoint if the changes in feed flow are included.
