4基于RX485的温度采集与显示

毕业设计论文基于RS485的多机温度采集与显示陈红香指导老师姓名：晏文靖专业名称：电子信息工程技术班级学号：07136337论文提交日期：2010年01月07日论文答辩日期：2010年01月13日2010年01月13日I【摘要】温度是工业控制中主要的被控参数之一，特别是在冶金、化工、建材、食品、机械、石油等工业中，具有举足重轻的作用。随着电子技术和微型计算机的迅速发展，微机测量和控制技术得到了迅速的发展和广泛的应用。单片机具有处理能强、运行速度快、功耗低等优点，应用在温度测量与控制方面，控制简单方便，测量范围广，精度较高。多机温度监测系统可实现对多点温度的测量，并能根据设定值对环境温度进行调节，实现控温的目的。本设计基于DS18B20传感器的温度测量和AT89S52单片机的控制装置，通过MAX485通信模块将温度数据传回计算机控制端，从而实现对环境温度进行监测。本设计就是利用一台PC机与两块单片机所组成的主从式温度监测系统。在本系统中上位机以PC和Windows操作系统为软硬件资源，下位机采用ATMEL公司的AT89S52，总线采用的是测控系统常用的RS-485。【关键词】AT89S52PC机与单片机通信MAX485II【Abstract】Temperatureisthemainaccusedintheindustrialcontroloneoftheparameters,especiallyinthemetallurgical,chemical,buildingmaterials,food,machinery,oilindustry,hasheldtheroleofheavy-lightfoot.Aselectronictechnologyandtherapiddevelopmentofmicro-computer,computermeasurementandcontroltechnologyhasbeenrapiddevelopmentandwideapplication.SCMhasadealcanbestrong,fast,lowpowerconsumptionadvantages,applicationsintemperaturemeasurementandcontrol,controlissimpleandconvenient,measuringawiderangeofhighprecision.Multi-machinetemperaturemonitoringsystemcanrealizethemulti-pointtemperaturemeasurements,andaccordingtosetvaluetoadjusttotheambienttemperaturetoachievetemperaturecontrolpurposes.ThedesignisbasedonDS18B20sensortemperaturemeasurementandcontrolunitMCUAT89S52,throughtheMAX485communicationmodulethetemperaturedatabacktocomputer-controlledside,thusbringingabouttheambienttemperaturemonitoring.ThisdesignistheuseofaPC,andcomposedoftwomaster-slavemicrocontrollertemperaturemonitoringsystem.Inthissystem,hostcomputerandtheWindowsoperatingsystemtoPChardwareandsoftwareresources,thenext-bitmachineusingATMELCorporationAT89S52,thebususesacontrolsystemcommonlyusedinRS-485.【KeyWords】AT89S52PCandSingle-chipcommunicationMAX485III目录绪论......................................................1第1章系统设计原理及要求..................................21.1设计思路........................................................21.2总体设计思路框图................................................21.3各部分组件说明..................................................2第2章AT89S52单片机的原理与结构...........................32.1AT89SXX系列单片机的内部结构....................................42.2AT89S52单片机的引脚功能........................................42.2.1I/O端口线输入输出引脚.....................................42.2.2控制线控制引脚............................................42.2.3外接晶体线................................................52.3AT89S52存储器组织..............................................52.4AT89S52程序存储器..............................................52.5AT89S52的复位方式..............................................62.6AT89S52的时钟电路..............................................6第3章串口通信的基本原理..................................73.1串口通信的有关概念..............................................73.2RS-232有关的串行通信概念.......................................73.3与串行口有关的SFR..............................................73.3.1串行通信控制寄存器SCON....................................73.3.2电源控制器PCON............................................83.4串行口的工作方式................................................83.5串行口的初始化.................................................103.5.1串行口波特率.............................................103.5.2初始化步骤...............................................10第4章DS18B20温度传感器..................................114.1DS18B20的简介.................................................114.2DS18B20的特点.................................................114.3DS18B20的封装结构.............................................114.4DS18B20的测温原理.............................................124.5DS18B20与单片机的典型接口电路.................................124.6DS18B20的软件设计.............................................13第5章定时/计数器与中断的原理及应用.......................145.1定时器/计数器有关的概念........................................145.1.1与T/C有关的特殊功能寄存器...............................145.1.2定时器/计数器的工作方式..................................15VI5.1.3定时器/计数器的初始化....................................165.2中断有关的概念.................................................165.2.1中断源...................................................165.2.2中断的控制................................................175.2.3中断响应..................................................18第6章硬件电路其他元器件简介.............................196.1单片机的最小系统...............................................196.2数码管的显示电路...............................................196.3MAX485串口通信电路............................................206.3.1MAX485芯片简介...........................................206.3.2通信方式.................................................216.3.3与PC机通信方式..........................................22第7章系统软件的设计与实现方法...........................237.1软件的使用.....................................................237.1.1AT89S52的编程器的使用....................................237.1.2串口调试助手V2.2的使用方法...............................237.2程序设计框图...................................................237.2.1DS18B20温度采集设计......................................237.2.2PC机与单片机的通信程序设计...............................24第8章调试...............................................278.1调试环境....................................