Research Of Intelligent Temperature Control Technology For Accelerating Rate Calorimeter

In chemical industry, exothermic reactions take place unexpectedly and were hardly controlled during the process of production and storage. And these reactions cause accidents because of the heat gathered from exothermic reactions. ARC can simulate the chemical reaction and evaluate the thermal hazard of chemicals. It is the key that controlling temperature of the experimental sample precisely in the experiment.Nonlinearity, time-varying, long time delays and asymmetry are the character of indirect resistance heating. People do lots of researches to improve its performance, so that it can be used widely. All those algorithms such as genetic algorithm, predictive control algorithm and fuzzy control algorithm become the foundation of precise temperature controlling in ARC.During the operation of ARC, the experimental sample will be heating up at a certain rate, but after a while the temperature should be held for a while. Considering using indirect resistance heating as heating method in ARC, it’s hard to realize the control requirements. Taking all these difficulties above and the structure of ARC into consideration this topic design a measurement and control system with PC and PLC and the hardware system. To meet the demands of temperature control of ARC, the working process is divided into three stages:heating stage, holding stage and transition stage. Accordingly this topic adopts dynamic sectional fuzzy control strategy, fuzzy control strategy based on GPC and temperature control in transition stage based on dynamic sectional control for each stage above. And the experimental result shows these strategies work well.This topic take the312CPU which is a serial of SIMATIC S7-300as the core controller and the program is designed based on modular design. The program includes the subroutine of temperature and pressure collecting, PWM generating, working state monitoring and filtering. PLC realize the strategies mentioned above during the timing interrupt service routine of OB35. The monitoring software of host computer, which has the functions of monitoring the operation state of experiment and storing experimental data, is set up by KingView produced by WellinTech development kit.The results of operation of the monitoring software for ARC show that the measurement and control system with friendly human-machine interface works steadily, and the temperature control system meets the requirement of temperature control of ARC. The historical data and real time data can be inquired expediently.