Abstract: In process industries, the automatic controllers has been introduced as an efficient controllers. PID controllers are the most widely used controllers because of their robustness and simplicity and economical. One of the major controlling parameter in industries are considered to be the level process. In today’s industrial environments ,level measurements have the wide variety needs and applications.In this paper, the main objective is the comparison of tuning of PID to maintain the level of water in the liquid tank. The analysis has been done using Ziegler-Nicholas(ZN), Internal Model Control(IMC) and Chien, Hrones and Reswich(CHR) methods. The comparison is done between the performance criteria and time domain specifications. These parameters are implemented in MATLAB platform and found that the IMC has outperformed well when compared to other controllers.

Keywords: PID controllers, IAE, ISE, ITAE, MATLAB.