Design of de-coupler for an interacting tanks system

Abstract

The dynamic behaviour of two tank interacting system was studied by the introduction of a step change in the manipulated variable (flow rate) and measuring the controlled variable by development of the suitable mathematical model of the system. This paper describes how the effect of the interaction of this interacting system is minimized by the design of the suitable de-coupler for the system and also includes the analysis of the interacting loops between the controlled variable that is liquid level of both tank and manipulated variable that is inlet flow rate. Generally in two tank interacting system there is no inlet flow rate for tank two , but this paper simplifies the industrial interaction problem where different tanks has different inlet and this is done by the help of relative gain array method. The result exemplifies that the gain of each loop is reduced approximately half when the opposite loop is closed and the gain of other loop changes the sign when the opposite loop is closed. Thus the decoupling is the most appropriate method for achieving minimal interaction and is most efficient method.