Design And Experimental Research On Electric Heating Temperature Control System

Now, the electric heating temperature system is an important part ofchemical companies’ production process, the temperature control is directly relatedto the quality of the final products, and it is related to whether the system can runsafely and effectively or not and the safety of persons and property. Therefore, it isnecessary for the electric heating system to control temperature effectively in order toensure the quality of the product and prevent accidents caused by temperature controlproblems.As a common intelligent control, fuzzy PID control has a number of successfuluses in the experimental system, and achieves the desired results. And in thetraditional experimental system, it compiles PID control algorithm in the MCU or asimple controller to simulate the actual system. Finally, it achieves the results by thecontroller itself or the host machine. This method is simple and easy to understand,but the final temperature control indicator is hard to meet the practical requirements.This article chooses the heating process for the raw material of sorbitol productionprocess as a reference object, selects the raw reaction temperature as the mainparameters, designs system and uses the Siemens S7-300PLC as the main controller.It directly uses its own programming language to finsh the fuzzy PID controlalgorithm, control the system and improve the temperature control indicators of thesystem. The ultimate realization of the temperature control indicators including theovershoot is less than2%, the rise time is less than15min, the precision of control isabout150±3℃. The main content of this theory includes some aspects as follows.（1）Using the fuzzy PID control method to control the electric heatingtemperature system, simulating and analysing by two kinds of fuzzy PIDcontrol way. Such as mixed fuzzy controller and common PID structure,fuzzy self-tuning technology for common PID parameters. Finally, it couldelect the fuzzy PID control algorithm of this article by comparing thesimulation results of the two algorithms. （2）Designing and building the electric heating temperature system,including the design of the electric heating device, host monitoring system,the lower machine PLC control system and on-site control system. It couldreal-time react the changes of the temperature and return PLC and system’smonitoring interface in time by this system. Meanwhile, PLC made thejudgment by programmed. The SCR regulator controlled the final outputvoltage value by the output signal from PLC.（3）The lower computer program could be designed by the SiemensStep7software, it could accomplish data acquisition, control algorithm, thesignal output in the PLC. Meanwhile, the Configuration Software Realinfowas used to complete the PC monitoring interface, including the masterinterface, the alarm interface, the trend curves, the data query for a total offour interface operations.（4）The data and curve were achieved from experimenting by the SCRregulator manual mode and automatic mode. It could arrive at a finalconclusion by analysing and comparing against their overshoot, rise time andaccuracy.