Design of HMI Based on PID Control of Temperature Nikunj Mehta M.Tech (Embedded System and VLSI Design) C.S.P.I.T, CHARUSAT University Changa, Gujarat, India Dharmendra Chauhan Faculty of Electronics & Communication C.S.P.I.T, CHARUSAT University Changa, Gujarat, India Sagar Patel Faculty of Electronics & Communication C.S.P.I.T, CHARUSAT University Changa, Gujarat, India Mr. Siddharth Mistry Product Engineer, Teq Diligent Product Solution Pvt. Ltd, Ahmedabad, Gujarat, India Abstract: One of the most used applications is Human Machine Interface in many industries. It has been recognized that our daily lives will be improved with various IOT applications in healthcare, agriculture, public sector, automation etc. Human Machine Interface that is HMI can be an example of IOT related applications. With web based GUI we can demonstrate HMI. The software components use here are Linux, Web based GUI, RL78 controller. To demonstrate industry application we put PID loop for control of temperature. Keywords: HMI, PID, QT, Temperature control, Thermocouple I. INTRODUCTION One of the most used application of Internet of Things is Human machine interface. For data management SQLite is used. Data to be stored are PID parameters, temperature data from RTD and Thermocouple. Temperature of plant can be maintained by PID loop in 16-bit controller. For PID control closed loop method Ziegler-Nichols can be used. Two techniques for controlling temperature are Manual Tuning and Auto tune PID. In manually tuned PID the control parameters are set manually by observing characteristics and behaviour of controlled device. In Auto tuned PID controller automatically determines the behaviour of device from past samples. In Auto tune PID control parameters are set by controller automatically. We update these control data in database and we can observe temperature of plant in Beagle bone. Graphical User Interface (GUI) is developed in QT application. Design for display of set temperature and actual temperature is developed in QT at server. II. WORKING OF HMI The aim of this design is to monitor the status of plant from remote location. PID controller is used to maintain the temperature. There are two modes manually tune PID and auto tune for PID tuning. This temperature value is to be displayed on server through RS-485 serial communication. MAX31855 IC is used as a convertor and uses SPI protocol to transfer temperature data to controller. The following is a Block Diagram for complete system. The parameters of PID controller can be set by HMI touch- screen display. Based on the difference between set temperature and actual temperature, PID controller gives output to minimize the error. The bulb released energy in the form of light and heat. Therefore, whenever actual temperature goes beyond set temperature bulb will be off. Hence, bulb will be on and off based on the PID output [1]. The parameters Kp, Ki and Kd plays a vital role in controlling PID controller output. These parameters are set based on the characteristic of actuator. For different actuators in different condition same parameters can’t be work. The bulb will be continuously on and off to maintain the desired temperature. RS-485 SPI T+ T- THERMOCOUPLE Fig.1 Block Diagram of HMI These data of actual temperature and parameter values are stored in local database. Hence, whenever it needed HMI will get data easily. The actual temperature is GUI in BEAGLE BONE TEMPERATURE SET TEMPERATURE 40 35 CONTROLLER MAX 31855 BULB International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 http://www.ijert.org IJERTV6IS050074 (This work is licensed under a Creative Commons Attribution 4.0 International License.) Published by : www.ijert.org Vol. 6 Issue 05, May - 2017 117