In this paper，it introduced the composition principle of DC motor SR system which is mainly composed AT89C51 microcontroller series.It’s mainly study of the motor drive and speed data acquisition module based on Microcontrollers to designed the core control system, This control system mainly include hardware devices and software control two parts,This system mainly include AT89C51 Microcontrollers, imitate the control plank, PWM, Photoelectric Sensors and DC motor.and introduces some relative knowledge upon the DC motor, PWM adjust of the basic principles and methods.This system uses Infrared photoelectric sensor as speed detecting sensor,uses PWM signal as control output to regulate speed.and the corresponding electronic circuit and software flow are also given.
The adoptive electronics components is simple and widespread, and the circuit conjunction is simple, installing to adjust to try easy, measure result precision, therefore have the very high and practical value.
Key words: DC machines, PWM, Pphotoelectric , AT89C51
