数字PID控制器在温度控制系统中的应用

Application of digital PID controller in temperature control systems

针对传统电炉温度控制系统控制精度、控制能力等较低的现状,设计一种上位机监控采用组态王软件,下位机采用西门子PLC的电炉智能温度控制系统。系统采用热电偶扩展模块EM231采集现场温度,利用PLC内嵌的PID控制器和外部温控电路实现恒温控制。详细阐述了系统的硬件结构、工作原理以及PID控制算法的实现。系统具有人机交互良好、性能稳定、控温精度高、易于操作维修、自动化程度高等特点,有效地实现了电炉温度的自动控制,具有良好的实用价值。

According to the lower present condition that the temperature control accuracy and the craft control ability of the traditional furnace temperature control system, a furnace＇s intelligence temperature control system which was presented,Siemens S7-200 PLC is used as the controlling-core and the configuration soft-ware is used as the human- computer interface. The thermocouple extension EM231was used to collect temperature, the use of PLC embedded PID controller and external temperature control circuit to achieve constant temperature control. The constitution of the system, Principle and Implementation of PID control algorithm are described in details. The System has the advantage of perfect human-machine interface, high dependence, simple operation and high automation, realizing effective implementation of the furnace temperature of automatic control, having a good practical value.