A proportional–integral (PI) controller is used in a liquid-level control system. The process transfer function is G(s) = 2/(4.8s + 1), the gain of the control valve is 0.08 and the reset time of the...

A proportional–integral (PI) controller is used in a liquid-level control system. The process transfer function is G(s) = 2/(4.8s + 1), the gain of the control valve is 0.08 and the reset time of the PI controller is τI = 2. Use the Simulink to find the step response curve to a unit step change in the inlet flow rate for each value of the controller gain K_c
= 3, 10, 20, 60. To construct the PI controller block in the Simulink, select the PID block from the Simulink → Continuous submenu in the Simulink Library Browser and drag the block to the block diagram in the editor window. Double-click the PID block to set the controller parameters. Set both the filter coefficient N and the derivative time to zeros