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

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.