基于热电偶的温度控制系统.doc

本科毕业设计 题目:基于热电偶的温度控制系统 Title:Thermocouple temperature control system based on  摘 要 本设计是采用K型热电偶为温度检测元件的单片机温度控制系统。 硬件电路包括：电源模块、温度检测模块、信号调理模块、A/D转换模块、键盘/显示电路模块、温度控制模块。工作过程如下：热电偶检测炉内温度，采集信号经过放大调理后送入0809进行模数转换，然后送入单片机并实时显示温度，同时从键盘输入系统温度设定值，将设定值与实际测量值进行比较会得到一个偏差值，将此偏差值进行PID处理，处理后的控制量送给继电器。继电器内的双向可控硅在给定周期T内具有不同的导通时间，这是由双向可控硅控制极上的触发脉冲控制的，这个触发脉冲是8051的P1.3引脚上产生的，经过零同步脉冲同步后经光耦管和驱动电路输出到可控硅的控制极上，从而改变加热的时间，达到温度控制的目的。 软件部分包括主程序、中断服务程序、中断服务程序、显示程序、键盘扫描程序等。 通过实践操作表明，本设计在误差范围内实现了对控制对象的温度控制。 关键词： AT89S51单片机, 热电偶, A/D转换, 直流电源，温度自动控制 Abstract The design of temperature control system using K type thermocouple for temperaturesensing element. The hardware circuit includes: a power supply module, temperature detecting module,signal conditioning module, A/D conversion module, keyboard and display circuitmodule, temperature control module. Work process is as follows: the temperaturethermocouple testing furnace, collecting signal after amplifying and conditioning into0809 analog to digital conversion, and then sent to the MCU and real-time temperature display, and keyboard input from the system temperature setting, thesetting value is compared to a deviation value and the actual measured value, thedeviation value of PID processing, control the amount of treated for bidirectional thyristor. A bidirectional controlled silicon with different guide in a given period T time,which is composed of a bidirectional thyristor control pole of the trigger pulse control,this trigger pulse is 8051 on the P1.3 pin, after zero synchronization after controloptocoupler tube and drive circuit to the pole of the controlled silicon, therebychanging the heating time, achieve the purpose of temperature control. The software system includes a main program, interrupt service program, interrupt service program, display program, keyboard scanning procedures. Through the practical operation shows that, the design is in the range of error to achieve the control ob