80C51单片机的一个简单PID控制程序，用的是位置式，配合DS18B20数字式温度传感器，达到的效果是控制加热炉温度保持在恒定值，精度为正负1度。-80 c51 a simple PID control program, use the position type, cooperate with DS18B20 digital temperature sensor, the effect of control furnace temperature kept at a constant value, the accuracy of plus or minus 1 degree.