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I摘要本文主要设计了一种基于单片机的锅炉液位控制系统，它以STC89C52单片机作为核心控制器，通过STC89C52单片机，温度传感器、压力传感器和模数转换器，数码管显示等硬件系统和软件设计方法实现具有液位检测报警和控制双重功能.本系统在设计中主要有水位检测、温度检测、压力检测、按键控制、水位控制、显示部分、故障报警等几部分组成来实现液位控制。主要用液位传感器检测液位，用DS18B20温度传感器来检测水温，用三个控制按键来实现按健控制，用三位7段LED显示器来完成显示部分，用MOC3041双向可控硅来控制水泵的开关，用压力传感器检测锅炉内部压力，并且通过模数转换把这些信号送入单片机中。把这些信号与单片机中内部设定的值相比，以判断单片机是否需要进行相应的操作，即是否需要开启水泵，来实现对液位的控制,从而实现单片机自动控制液位的目的。本设计用单片机控制易于实现锅炉液位、温度和压力的控制,而且有造价低、程序易于调试、一部分出现故障不会影响其他部分的工作、维修方便等优点。关键词：STC89C52单片机,液位控制，显示，报警IIABSTRACTDesignedinthispaperisaboilerliquidlevelcontrollsystem,whichSTC89C52asacontroller,throughhardwareandsoftwaredesign,suchasSTC89C52singlechip,temperaturesensor,pressuresensorandADC,asystemofdigitaldisplay,reachtoliquidleveldetectionandalarmdualfunctioncontrol.Thedesignofthesystemaremainlyincludethewaterleveldetection,temperaturedetection,pressuredetection,keycontrol,waterlevelcontrol,display,faultalarm,suchasafewpartstoachievethelevelcontrol.Detectionofthemainlevelwiththewaterlevelsensors,temperaturesensorsDS18B20isusedtodetectedwatertemperature,withthreecontrolbuttonstoachievethehealthcontrol,withthree7LEDdisplaytocompletethedisplay,usingMOC3041TRIACtocontrolthecirculatingpumpswitch,withpressuresensorsdetecttheinternalpressureoftheboiler.Throughanalog-to-digitalconversiontakethesesignalsintothesinglechip.Thesesingle-chipsignalandtheinternalsetofvaluescomparedtodeterminetheneedforthecorrespondingsingle-chipoperation,namely,theneedtoopenthepumptoachievethelevelofcontrol,thusinordertoachievethepurposeofautomaticcontrolbysingle-chipsolution.Thedesigniseasytoimplementsingle-chipboilerliquidlevelcontrol,temperatureandpressurecontrol,anditslowcostandeasytodebugtheprocedure,partofthefailurewillnotaffectotherpartsofthework,maintenanceconvenience,andsoon.KEYWORDS:stc89c52Singlechipmicrocomputer,levelcontrol,display,alarmIII目录第一章绪论...............................................................11.1锅炉液位控制的背景..................................................11.2锅炉液位控制国内外发展概况..........................................21.2.1国内发展概况..................................................21.2.2国外发展概况..................................................21.3本课题研究目的及意义................................................31.4系统简介...........................................................3第二章.主要芯片介绍........................................................52.1单片机STC89C52介绍.................................................52.1.1STC89C52单片机的外部引脚说明.................................52.1.2STC89C52RC单片机的中断系统...................................72.1.3选择使用STC89C52RC的原因.....................................92.2芯片74LS164介绍....................................................92.2.174LS164的引脚图及引脚功能：.................................102.2.274LS164的内部功能图........................................102.2.374LS164的真值表.............................................112.2.474LS164有如下特点：.........................................112.3模数转换器A/D0809.................................................122.3.1ADC0809的逻辑结构...........................................122.3.2ADC0809的通道选择...........................................122.3.3ADC0809的引脚图及各引脚作用.................................132.4温度传感器DS18B20.................................................142.4.1DS18B20的内部结构及管脚图...................................142.4.2DS18B20技术性能描述.......................................152.4.3DS18B20的温度处理过程.......................................162.5LED数码管显示....................................................172.5.1LED数码管显示器的结构.....................................182.5.2LED数码管显示器的显示段码...................................182.5.3LED显示器的参数............................................19IV第三章．锅炉液位控制的硬件设计............................................213.1系统硬件设计的总体方案及框图.......................................213.1.1系统硬件设计总体方案.........................................213.1.2系统设计的总体框图...........................................213.2键盘控制电路设计..................................................223.3复位电路设计......................................................233.4显示电路的设计....................................................243.4.1静态显示.....................................................243.4.2动态显示.....................................................253.4.3该设计中显示电路的选择.......................................253.5液位控制电路的设计................................................263.5.1液位控制电路的工作原理及液位控制状态图.......................263.5.2液位控制的控制电路...........................................273.5.3液位控制中的“虚假水位”.....................................283.6测温电路及温度传感器的选择........................................313.6.1温度传感器的选择.............................................313.6.2温度检测电路.................................................32第四章.软件设计及试验运行结果和讨论.......................................334.1系统的软件设计....................................................334.2试验调试及运行结果.................................................344.2.1硬件调试.....................................................344.2.2软件调试.....................................................354.2.3软硬件实时调试...............................................354.2.4系统