PI settings for integrating processes based on ultimate cycle information

This paper presents simple proportional integral (PI) tuning formulas for i ntegrating processes. They are based on the knowledge of the ultimate gain and the ultimate period. This information can be obtained by performing a c lassical ultimate cycle experiment or by using the relay feedback technique . Refined settings are proposed when the oa process gain is known. The tuni ng method is based on a maximum peak resonance specification. The results a re compared to those obtained with the Ziegler-Nichols settings. Coherent p erformances are obtained over a wide range of linear integrating processes.