OPTIMAL PI TUNING RULES FOR LIQUID FLOW PROCESS CONTROL SYSTEM USING COHENCOON’S (C-C), ZIEGLER-NICHOLS’S (Z-N) AND TAKAHASHI’S TUNING METHOD

Abstract

The purpose of this paper is to find the optimum PI controller tuning method and tuning rule for bench scale flow system. In this paper highlighted tuning method using Ziegler-Nichols (Z-N), Cohen-Coon (C-C) and Takahashi in order to find which one is best tuning method for Liquid Flow Process Control Training System Model SE270-1. The control system for this bench scale model not yet been studied in detailed since its usage only restricted to educational purpose. Hence, two type of controller such as P and PI, two PI tuning rules and three tuning methods were analyzed based on overshoot, settling time and rise time. Open loop test has been performed by using tangent method and reformulated tangent method. The open loop test was used to calculate the Response Rate (RR), Dead Time (Td) and Constant Time (Tc) where the value was used in tuning method. Three performance tests are done using three different gain values which were PI and PI multiply by four. PI controller with Takahashi tuning method with gain value multiply by four is choose as best controller, the response obtained is stable and robust with no oscillation, no overshot and short rise time and settling time.