基于单片机的液位控制系统设计的-毕业设计论文

I摘要本课题是基于单片机的液位控制系统的设计，使用在日常生活和工业应用中广泛应用的水塔作为被控装置，水塔液位和水压作为被控对象；本设计采用液位检测装置和电容式差压变送器对液位高度和压力进行实时检测并传送到单片机进行实时处理，从而使水塔水位自动保持在指定的范围。其中，液位控制系统的硬件电路主要包括水位和水压检测电路、A/D转换电路、键盘显示电路、报警电路、电机控制电路等五大部分；该系统使用电容式差压变送器对水塔水压进行检测并将检测到的信号送给A/D转换器，A/D转换器将对应的模拟电压信号转换成数字量传给单片机AT89C51进行处理，单片机将处理的结果通过数码管显示出来，并完成对排水、抽水电动机的控制；在单片机进行实时处理的同时，可以通过按键对控制系统进行相应的功能切换。该系统各个部分的硬件电路采用C51语言编写控制程序，从而实现使用键盘调整被控参数水压的上、下限以及软件复位功能；利用四位一体共阴极数码管显示水压；通过逻辑代码达到对电机控制电路的控制，使电机在一定的条件下进行抽水或者排水操作；最终使被控对象被控制在指定的水位和水压范围内。在将系统的硬件电路设计和软件程序设计完成后，需要将硬件电路部分和软件程序部分结合起来进行液位控制系统的调试，如果发现问题，就需要找到合适的解决方案，修改错误的部分；并且将这两者结合进行液位控制系统仿真结果的测试，观察实验的结果是否符合课题的设计要求，不然修改不符合课题要求的部分，最终达到液位控制系统的课题目标。关键词：AT89C51单片机；A/D转换；液位控制IIAbstractThistopicisthedesignofcontrolsystembasedonsingle-chipliquidlevelcontrol,usingthetowerasacontrolleddevicewhichisoftenseenindailylifeandindustrialapplication,theliquidlevelofthewatertowerandwaterpressureastheobject;thisdesignusestheliquidleveldetectiondeviceandcapacitivedifferentialpressuretransmittertomonitortheliquidlevelandpressureandreal-timeprocessing,sothatthewaterlevelautomaticallykeepsinthespecifiedrange.Thehardwarecircuitofcontrolsystemmainlyhasfiveparts,whichincludeswaterpressureandliquidleveldetection,A/Dconverter,keyboarddisplaycircuit,alarmcircuit,motorcontrolandsoon;thesystemusescapacitivedifferentialpressuretransmittertodetectthetowerpressureandthedetectedsignalissendedtotheA/Dconverter;A/DconverterwillconvertthisanalogvoltagesignalsintodigitalsignalswhichsendtotheAT89C51single-chip,andthemicro-controllerprocessestheresults,whichcanusethenixietubestodisplay,andaccomplishthecontrolofdrainageandpumpingmotor;Atthesametimeofreal-timeprocessingintheSCM,thecorrespondingbuttoncanswitchtodifferentfunctionsofthecontrolsystem.EachpartofthehardwarecircuitofthesystemusesC51languagetoprogram,soastorealizetheuseofthekeyboardtoadjustthecontrolledparametersofupperandlowerlimitpressure;usingoneofLEDtodisplaythepressure,throughthelogiccodetocontrolthecontrolcircuitofthemotor,themotorwillpumpordrainunderacertaincondition;ultimatelythewaterpressureandwaterpressurewillbecontrolledinaspecifiedrange.Afterthedesignofhardwarecircuitandsoftwareprogram,debuggingliquidlevelcontrolsystemcombininghardwarewithsoftwarepartisneeded;iferrorsarefound,findtherightsolution,modifythewrongpart;alsothiscombinationofliquidlevelcontrolsystemsimulationresultsneedtest,andobservetheexperimentalresultswhetherornottheseresultsareinconformitywiththerequirementsoftheprojectdesign;Otherwise,modifyingthepartthatdoesnotmeettherequirementsoftheproject,andultimatelytheaimofliquidlevelcontrolsystemwillbeachieved.Keywords:AT89C51singlechipmicro-controller;A/Dconversion;liquidlevelcontrolIII目录摘要.....................................................................................................................................IAbstract.....................................................................................................................................II第1章绪论..............................................................................................................................11.1课题的意义.................................................................................................................11.2国内外的研究动态.....................................................................................................21.3课题的目的和预期目标.............................................................................................3第2章系统整体方案设计......................................................................................................4第3章硬件电路设计..............................................................................................................63.1AT89C51单片机.........................................................................................................63.1.1单片机的功能和特点......................................................................................63.1.2时钟和复位电路..............................................................................................83.2水位检测电路和水压检测电路.................................................................................93.2.1水压检测电路以及控制仪表..........................................................................93.2.2水位检测电路................................................................................................103.3A/D转换设计............................................................................................................113.3.1A/D转换器介绍.............................................................................................113.3.2A/D转换电路.................................................................................................133.4数码管显示和键盘电路...........................................................................................143.4.1键盘电路........................................................................................................143.4.2数码管显示电路............................................................................................153.5报警电路.................................................................