Comparative Study of Single-loop Control and Cascade Control of Third-order Object

Abstract

For third-order system can describe most of the controlled objects in nature, this paper designs a third-order object control system which contains three tanks. In the control system, Simatic S7-200 PLC is employed as the hardware controller. And the single-loop control system and cascade control system are established respectively in order to compare their control characteristics. Through comparing and analyzing with two control methods, experiment results show that cascade control system has better performance than single-loop control system no matter where the disturbances get into control system.