In the part of modeling system, the Integral System
Response (ISR) [4] is used for the Interactive coupled-tank
process. According to equation (3), it is able to illustrate the
second order system with two poles and without zero thus, the
modeling method by ISR will be inputted the step signal for
three times.
For the part of two degree of freedom controller is consists
of the feedback PID controller and feed forward pre-filter
controller. The mathematical model of controller that obtained
by ISR is designed the controller by root locus technique. [5]
Feedback controller
2