为了实现水温控制系统的设计要求，通过对各模块电路方案的比较及论证，最后确定了这种以STC89C52单片机为核心的硬件电路，选用DS18B20温度传感器测量水温，该传感器分辨温度可达0.0625℃，750ms数字转换，采用单总线连接，测量精度高，转换时间快，就有极强抗干扰纠错能力，在加上PID算法的精确控制，其精度足以满足题目要求。显示模块采用12864点阵液晶，并行接口，编程容易，美观大方，可实现水温及其随时间变化的实时曲线的显示功能。除单片机可实现的恒值自动控制外，该系统还可通过键盘设定水温，在短时间内迅速加热或制冷。本系统实现了对一升水的温度控制，即在10℃—70℃量程范围内对每一点温度的自动控制以保持设定的温度基本不变。-In order to achieve the design requirements for water temperature control system, by comparing each module circuit programs and feasibility studies, finalized this to STC89C52 microcontroller core hardware circuit, the choice of DS18B20 temperature sensors measure temperature, the temperature sensor resolution up to 0.0625 ℃, 750ms to-digital converter, a single bus connection, high accuracy, fast conversion time, there is a strong anti-interference correction capability, coupled with precise control PID algorithm, its accuracy is sufficient to meet the subject requirements. 12864 dot matrix LCD display module, a parallel interface, easy programming, nice, can achieve real-time curve temperature and changes with time display function. In addition to the constant microcontroller can achieve automatic control, the system can also set the temperature via the keyboard, the rapid heating or cooling in a short time. The system realizes the temperature control of a premium, that is, within 10