基于PT100的温度测控系统的设计与仿真

Design and simulation for temperature measurement and control system based on PT100

摘要:

温度测控在现代工业生产过程中起着非常关键的作用,也是设备按照预定的方案正常运行的必要条件。针对目前工业设备温度控制系统电路稳定性差、精度低、实时显示效果差等缺点,设计了基于PT100的温度测控系统。该系统采用电桥对PT100传感器输出的电信号进行采样；采用LM741设计差分放大电路消除线路阻抗引起的测量偏差；采用ADC0808逐次逼近法消除温控系统的非线性误差；采用STC高性能单片机作为主控芯片进行数据处理、并能够实时显示温度数值和具有设定上下限的功能,最后通过继电器实现对被控对象通断进行控制。系统通过Proteus软件仿真运行验证了电路设计的合理性、温度显示数据的高精度和系统正常运行的鲁棒性。

Abstract:

Temperature measurement and control plays a very important role in the modern industrial production process, and is also the necessary condition for the normal operation of the equipment according to the scheduled scheme. The temperature measurement and control system was designed for the disadvantages (e.g. poor circuit stability, low precision and poor real-time display effect) of the current temperature control system of industrial equipment. The system uses electric bridge to adopt electrical signals from PT100 sensor, adopts LM741 to design differential amplifier circuit to eliminate measurement bias caused by line impedance, adopts ADC0808 successive approximation method to eliminate non-linear error of temperature control system, adopts STC high-performance single chip microcomputer as the main control chip for data processing, and can display temperature value in real time and have the function of setting upper and lower limits. At last, control on the controlled object through relay. The reasonability of circuit design, high accuracy of temperature display data and robustness of normal operation of the system are verified by the simulation operation of Proteus software.