说明：  本文叙述了现在几种成熟的PID控制算法，对PID控制器的设计进行了研究，包括对控制器的硬件选型和软件设计，对合适的硬件给予详细的介绍，对程序的运行给出详细的程序流程图。 功能PID控制器的核心选用了ATMEL公司的AT89C51单片机，通过合适的外接硬件来完成模拟数据量的采集处理，数据的模数数模转换，液晶显示，按键输入等。
(This paper describes several mature PID control algorithms, and studies the design of PID controller, including the hardware selection and software design of the controller, the detailed introduction of the appropriate hardware, and the detailed program flow chart for the operation of the program. The core of the functional PID controller is ATMEL MCU AT89C51, which completes the collection and processing of analog data, data analog to digital conversion, LCD display and keypad input through the appropriate external hardware.)