Well designed conventional PID controllers using Ziegler-Nichols method are having large overshoot and settling time. Significant research work has been carried out to improve the performance of closed loop response with PID controller so that it can be used for real time temperature control system using SCADA (HC- 900 Honeywell controller). Also performance of PID controller is investigated for different performance metrics such as Integral Square Error (ISE), Integral Absolute Error (IAE), Integral Time Absolute Error (ITAE), and Integral Time Square Error (ITSE) is presented and simulation is carried out. This paper explores basic concepts, mathematics, and design aspect of PID controller.