摘要：温度是表征物体冷热程度的物理量，是工农业生产过程中一个很重要而普遍的参数。由于温度测量的普遍性，温度传感器的数量在各种传感器中居首位。温度控制的发展引入单片机后，可以降低对某些硬件电路的要求。基于单片机的温度控制系统，可以实现对温度的精确控制。66640

    本文以温室为研究对象，以AT89C51单片机为核心所实现的温度控制系统具有自动完成数据采集、数据处理、数据转换控制、键盘终端处理及显示的功能。当温度低于目前的设定值时，PTC加热或停止加热。实际温度不在设定好的范围内时，系统会触发报警。温度控制采用的是双位控制，简单容易执行，在精度需求低的温室中，具有很高的可行度。    

本设计在调试之后并使用proteus进行仿真，仿真结果显示该系统原理可行。又在一个小空间进行试验，误差在1℃左右，结果符合预期。可以良好的控制稳定性和节约成本。

毕业论文关键词：单片机，温度控制，DS18B20，温室温度

Abstract：Temperature is the physical quantity characterizing the temperature extent of objects; it is an important and general parameter in industrial and agricultural production process. Due to the universality of temperature measurement, the quantity of temperature sensor occupies first place among various sensors. It can lower the requirements of some circuits after introducing the development of temperature control into microcontroller unit. It can also achieve precise control of the temperature, based on the temperature control system of microcontroller unit.

    In this article, greenhouse is the object of study. The temperature control system which takes AT89C51 as the core has the function of automatic complete data acquisition, data processing, data conversion control, keyboard terminal processing and display. When the actual temperature is below the set value, PTC starts heating, on the contrary, it stops heating. When the actual temperature exceeds the upper or lower limit, the system gives an alarm automatically. Temperature control is simple and easy with a dual position control. It is highly feasible in the greenhouse where the accuracy requirements are less strict.

    The results shows the principle is available after debugging the system and simulating in Proteus, we also conducted the same trial in a smaller room, and the error is about 1℃, which is in line with expectations. The system is stable, easy to control and cost-effective.

Keywords：microcontroller unit, temperature control, DS18B20, greenhousetemperature

目   录

1 引言 5

2 硬件系统总体方案设计 6

2.1硬件系统总体设计方案 6

2.2硬件系统的方案选择 6

3 控制系统硬件设计 7

3.1单片机 8

3.2 数字温度计DS18B20 8

3.2.1 DS18S20数字温度计的主要特性 9

3.3 4X4键盘 9

3.4数码管 9

3.5光电耦合器 11

3.6 双向晶闸管 12

3.7 PTC加热器 13

3.8 反相器7406 13

3.9双四输入与门74LS21 14

4 控制系统软件设计 14