PI controller tuning rules for optimal load disturbance response

This paper presents PI controller tuning rules for a set of typical linear and time-invariant low order process model types encountered in process industry. The model set consists of both integrating and non-integrating low order models with time delays. The rules are obtained for each model type by minimizing an integrated error due to a step load disturbance at the plant input and using a maximum sensitivity as a design parameter. The tuning method has been presented earlier, however, the tuning rules are new. The rules are presented as a function of maximum sensitivity and model parameters such as static gain and normalized time constant. Usefulness of maximum sensitivity as a design parameter is discussed and the tuning rules with a few examples are introduced.