Design of centralized PI control system for two variable processes based on root locus technique

Abstract

This paper describes the design of centralized controller for two variable processes. The two variable process structures are somehow different from the single variable processes. This difference is occurred because of interrelations between the variables present in the process. Hence, when a controller is planned for such systems, the relations amid the variables must be taken into consideration. This process is done in decentralized control system design. But decentralized control system works well when the interrelations between the variables are simple. If the interaction is strong, then the centralized control system is preferred since it uses a controller for each pair of input and output variables. The controller used in main diagonal works for improving the servo performance and off diagonal controller reduces the interrelation effect. So the performance is improved by minimizing the interrelation effects. The design process is easy to understand by field engineers working in industries. The simulation results are included in this paper to specify the efficacy of the proposed scheme.