American Journal of Engineering Research (AJER) 2017 American Journal of Engineering Research (AJER) e-ISSN: 2320-0847 p-ISSN : 2320-0936 Volume-6, Issue-9, pp-175- www.ajer.org Research Paper Open Access www.ajer.org Page 175 Optimization of Pid Controler In Temperature Control System Processes Pasteurization of Milk Hariyadi. Singgih (Electronic Engineering, Politeknik Negeri Malang, Indonesia) ABSTRACT : Pasteurization is one of the heating process done on fresh milk so it becomes a product that has a longer shelf life. By controlling the temperature in the pasteurization process is expected to be able to kill pathogenic bacteria that endanger human health, so it is important to do the temperature control. In manual and conventional controls cause temperature instability and possible many errors occur. So as to affect the quality of the production of pasteurization process of milk is not good. Therefore, in this study developed a controller to maintain temperature stability in milk pasteurization process. The control system used for this control is the PID control implanted on Atmega 16 to control electrically heating element actuators that get input from PT 100 temperature sensors. The test results for heating of milk starting from 30 ° C to 65 ° C. Using Tuning Ziegler Nichols method, Kp = 18, Ki = 0.45 and Kd = 180. The system was tested at temperature setting 65˚C and milk volume of 10 liter, with graph showing time rise (Tr) = 2400s, time delay Td) = 140 s, peak time (Tp) = 2700s, down time (Ts) = 3700 s, maximum overshoot (Mp) = 2 ° C and steady state error 1.5%. Keywords - Pasteurization, milk, PID-controller, censor , temperature. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 28 -08-2017 Date of acceptance: 13-09-2017 --------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION Background Of Problems Milk is an ingredient beverages that have high nutritional content but are vulnerable to bacteria so they are not durable and easily broken (stale) [1] Therefore, the need for milk processing to optimize the quality and durability of milk which could eventually reduce keruguian farmers in distributing milk and reduce manpower in processing the milk. One example is the pasteurization of milk processing. Pasteurization is a heating process performed on fresh milk so that it becomes a product that has a longer expiration. The pasteurization process may be performed under high temperatures or low temperatures which can be applied [1]. In the heating process by controlling the temperature is expected to be able to kill pathogenic bacteria that endanger human health and minimizing the development of other bacteria, either for heating or during storage [3]. Therefore, to overcome these problems required a tool pasteurized milk with the control system to obtain the desired stable temperature automatically. So it will be an effective and stable temperature corresponding requirements of pasteurized milk. In this study tested using methods LTLT (Low Temperature Long Time), which is heating the milk to a temperature of 63-65 ° C and maintained at that temperature for 30 minutes [3]. In order for the milk pasteurization process can be done automatically, the heating process is done using a controller with PID control. P (proportional), I (integral) and D (derivative) with the overall objective to accelerate the response of a system, eliminating the offset and produce large initial changes (oscillations). With the use of PID temperature controller can control the time efficiently and effectively and maintain stable temperature of the pasteurization process [9]. Research Objectives The purpose of research is to find the value optimization of PID control system using the method of milk pasteruisasi LTLT (Low Temperature Long Time), which is heating the milk to a temperature of 63-65° C and maintained stable for 30 minutes. [9].