本系统采用C51系列的89S52单片机为核心，通过设置89S52单片机的定时器产生脉宽可调的PWM波【2】，对阀门电机的输入电压进行调制，实现阀门开度的变化，进而实现了对液体流量的控制。单片机通过电磁流量计采集实际流量信号，根据该信号对其内部采用数字PID算法对PWM变量的值进行修改，从而达到对流量的闭环精确控制。-The system uses microcontroller 89S52 C51 series core, 89S52 microcontroller by setting the timer to generate pulse width adjustable PWM wave 【2】, input voltage of the valve to modulate the motor to achieve changes in valve opening, thus achieving The control of liquid flow. SCM actual flow through the electromagnetic flow meter signal acquisition, according to the signals of its internal PWM digital PID algorithm to modify the value of the variable to achieve precise control of the flow loop.