实时温度采集系统
I
摘
要
本课题主要介绍了基于DS18B20和串口通信技术的分布式远程温度监控系统。
DS18B20是Dallas公司推出的单线总线产品，最大的优点是只占用单片机的一个I\\O引脚，并且可以直接输出数字信号，而且精确度很高，所以很适合用于多点测温系统。
本课题采用单片机与计算机串口通信的方式来实现远程采集与控制的工作。通信采用RS485传输协议，并在计算机端将其转化为RS232从而能够与计算机串口连接。
单片机通过对测温器件DS18B20执行相应的操作来读取对应通道的温度，然后将读取到的温度通过串行口发送给计算机，计算机通过用Visual Basic6编写的软件读取到温度值后通过显示器显示出来，用户可以操作软件绘制温度曲线和温度列表，并能够将其保存到电脑硬盘上，还可以操作软件选择测温通道和测量分辨率等。
关键词 串口通信；分布式测温；DS18B20
II
Abstract
This subject introduces the serial based on DS18B20 and communication technology distributed remote temperature monitoring system.
DS18B20 is the 1-wire product of Dallas, the biggest advantages is the only occupants of one microcontroller’s I \\ O pins and can be directly output digital signal with a high degree of accuracy, so it suit for distributed temperature measurement system .
The subject based on the serial communication between the computer and the MCU. Transfer Protocol using RS485 communications and it will be converted into RS232 to connect to the computer.
The SCM through the DS18B20 to read the temperature, and then send it to the computer.The computer use the software which is made by Visual Basic6 to read the temperature and then display it.The user can use the software to make the curve and the temperature list,and the user can save them to the hard disk.The user also can chose the access and the temperature measurement resolution.
Keywords Serial Communication;Distributed Temperature;DS18B20
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目 录
摘 要 .................................................................................................................... II ABSTRACT ....................................................................................................... III 第1章 绪论 ...................................................................................................... 1 1.1 课题背景 .................................................................................................. 1 1.1.1 传统测温的介绍 ................................................................................. 1 1.1.2 计算机控制技术的发展 ..................................................................... 1 1.2 本章小结 .................................................................................................. 2 第2章 系统硬件结构 ...................................................................................... 3 2.1 51系列单片机系统简介 ......................................................................... 3 2.2 测温器件DS18B20介绍 ........................................................................ 3 2.3 串口通信技术的硬件基础 ...................................................................... 5 2.3.1 RS-232、RS-485简介 ................................................................... 5 2.3.2 器件MAX232介绍 .......................................................................... 7 2.3.3 器件MAX485介绍 .......................................................................... 8 2.4显示系统的硬件原理 ................................................................................ 8 2.4.1 串行寄存器74LS164功能 .............................................................. 8 2.4.2 数码管原理 ....................................................................................... 9 2.4.3 数字串行显示的实现 ..................................................................... 10 2.5 本章小结 ................................................................................................ 11 第3章 系统软件设计 .................................................................................... 12 3.1 总体程序设计思路 ................................................................................ 12 3.1.1 制定通信协议 ................................................................................. 12 3.1.2 下位机的程序设计思路 ................................................................. 12 3.1.3 上位机软件的程序功能 ................................................................. 14 3.2 下位机程序分块介绍 ............................................................................ 14 3.2.1 DS18B20的程序介绍 .................................................................... 14 3.2.2 串行口收发程序设计 ..................................................................... 17 3.2.3 LED显示模块 .............................................................................. 18 3.3 上位机程序分块介绍 ............................................................................ 18 3.3.1 MSComm控件的用法与详细介绍 ............................................. 18 3.3.2 界面设计 ......................................................................................... 19 3.3.3 串口收发程序设计 ......................................................................... 21
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3.3.4 绘图程序 ......................................................................................... 22 3.4 本章小结 ................................................................................................ 22 第4章 仿真与调试 ........................................................................................ 23 4.1 PROTEUS介绍 ..................................................................................... 23 4.2 原理图的输入 ........................................................................................ 23 4.2.1 工作界面 ......................................................................................... 23 4.2.2 绘制原理图 ..................................................................................... 24 4.2.3 编辑对象 ......................................................................................... 25 4.3 电路仿真 ................................................................................................ 26 4.4 本章小结 ................................................................................................ 27 第5章 PCB板的制作 ..................................................................................... 28 5.1 PROTEL简介 ........................................................................................... 28 5.2 原理图输入 ............................................................................................ 28 5.3 PCB板的制作 ........................................................................................ 29 5.3.1 PCB的结构 .................................................................................... 29 5.3.2 PCB布局 ........................................................................................ 30 5.3.3 PCB布线 ........................................................................................ 30 5.4 PCB板的电磁兼容设计 ........................................................................ 30 5.5 本章小结 ................................................................................................ 31 结论 .................................................................................................................... 32 参考文献 ............................................................................................................ 33 附录1 .................................................................................................................... I 附录2 ................................................................................................................. IV 附录3 硬件原理图 .......................................................................................... VII 附录4 硬件PCB图 ......................................................................................... VIII 附录5 实物照片 ............................................................................................... IX 附录6 PROTEUS仿真截图 .................................................................................. X 附录7 电脑软件界面 ....................................................................................... XI 附录8 电脑软件运行截图 ............................................................................. XIII 附录9 VB源程序 .............................................................................................. 15 附录10 单片机程序 .............................................................................. XXXVIII
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