The Design And Expeerimentation Research Of Programmable Electric Heat-tracing Controller

With the continuous development of modern industry technology, electronic heatas a kind of common technology has obvious advantages and has been widely used toreplace traditional ways of steam, hot water heating. Pipes, valves and instruments onfield in petroleum, petrifaction, nuclear power, fire protect and tunnel projects all needto maintain a certain temperature range. Temperature too high or too low will affectthe performance of the system. Stable and effective temperature control system is anessential condition on working normally. In this paper, according to projectrequirements and performance evaluation, an intelligent and programmabletemperature control system with electronic heat is designed for real-time and efficientcontrol based on STM32F series MCU with high performance and low consumption.Firstly, system requirements and parameters are analyzed and then the entirescheme is designed. The hardware based on STM32for intelligent and programmabletemperature control system with electric heating is illustrated at first.8channels fortemperature control circuits,8channels digital output circuit,8channels digital inputcircuit,7channels current sample circuit, RS485communication circuit, Ethernetcommunication circuit, industrial touch screen circuit and extern RAM circuit are allincluded in the hardware.Secondly, PC monitor software and embedded control algorithm software isdesigned based on the hardware above. First of all, the Real-time embedded systemuC/OS-II is ported on STM32MCU. And then application codes are designed on theuC/OS-II, such as function implementation, algorithm implementation, and low leveldrivers. At last, the signal sample, circuit control, real-time monitor andself-diagnosed are realized for the project requirements.Thirdly, porting and implement Modbus protocol is illustrated. The system isadopted standard Modbus protocol via series communication to network with hostcomputer and RTU modular which have efficient on intelligent and network forsystem control.Fourthly, the algorithm library for electronic heating temperature control isdesigned. It includes the self-tuning PID parameters, environmental temperature proportional PID control algorithm and heated object temperature switch controlalgorithm. The over current protect, over temperature protect, short circuit protect andwarning strategy are also designed.At last, the test platform is implemented for software and hardware test and getsverified successfully. And then the temperature controller with electric heating istested in the actual condition with PC configuration software. The experimental resultshows that the temperature controller is stable, reliable, realizes the expectedrequirements and satisfies the design requirements.