Effect of sampling time on PID controller design for a heat exchanger system

摘要

Temperature control is desirable in heat exchanger system due to fact that chemical processing plants requires certain level of temperature for a given for a particular processing. This research aims at the development of a PID controller for outlet temperature control of a heat exchanger system. The proposed controller was developed based on MIGO (M-Constrained integral gain optimisation) tuning algorithm and simulated using MATLAB/Simulink. The system model is represented using discrete time domain approach at specific interval of sampling time, the results obtained showed that an increase in sampling time gives a resultant increase in settling time for all operating conditions considered. Similarly the values of rise time increases with the increase of sampling time at no disturbance condition but decreases during the application of disturbance. Also the occurrence of overshoot and undershoot decreases as the sampling time increases at no disturbance condition except for a sampling time of 1.0 second, but for the disturbed condition, the overshoot and undershoot are not experienced as the sampling time increase.