说明：   由51单片机组成的数字控制系统控制中，PID控制器是通过PID控制算法实现的。51单片机通过AD对信号进行采集，变成数字信号，再在单片机中通过算法实现PID运算，再通过DA把控制量反馈回控制源。从而实现对系统的伺服控制。
(The 51 single-chip digital control system consisting of control, PID controller is implemented through the PID control algorithm. 51 SCM signal is collected by AD, into digital signals, then through the algorithm in the microcontroller PID operation, and through the DA to control the amount of feedback to the control source. The system in order to achieve servo control.)