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I基于PLC的住宅小区变频恒压供水系统摘要在当今的社会，随着我国经济的不断的快速发展，人们的生活水平在不断地提高。城市中各类基础设施的建设发展也在快速的发展。其中也对城市住宅小区的供水系统提出的更高的要求。变频恒压控制系统是我国住宅小区广泛应用的供水系统,传统的控制方式存在控制精度低、能耗大的缺点,研究设计的基于PLC控制的多泵循环变频恒压供水系统,采用可编程序控制器、变频器以及压力变送器等器件,完成逻辑控制、变频调速和数据采样等功能,使系统实现自动控制,达到节能的目的,提高了供水系统的质量。本设计根据小区的供水要求，设计了一套基于PLC的住宅小区水塔水位控制系统。该系统主要由可编程控制器（缩写为PLC）、变频器、液位开关、压力传感器及水泵等组成。本设计通过一台变频器控制三台水泵的启停以及调速。实现了供水水泵的软启动和供水水泵的工频运行与变频运行行之间的切换。通过压力传感器检测供水管网的压力，并将测量到的水压信号反馈回PLC中，与给定值进行比较后，经过PID运算，将运算结果送入变频器，从而实现对变频器的输出电压和频率的控制，通过控制变频器的输出电压和频率，来改变供水水泵电机的转速，进而改变供水量。当有火灾发生时，使三台水泵同时处于工频运行状态，以满足消防用水。该系统实现了居民用水的底恒压正常供水和火灾发生时的高恒压供水这俩种供水方式以及它们之间的自动切换。同时能够实现水位的自动报警等功能。本系统的设计不仅实现了供水过程的自动控制，同时也达到了节能的效益。关键词：可编程控制器PLC恒压供水变频调速IIResidentialfrequencyconstantpressurewatersupplysystembasedonPLCAbstractIntoday'ssociety,withtherapiddevelopmentoftheeconomyofourcountry,people'slivingstandardcontinuestoimprove.Inthecityconstructionanddevelopmentofallkindsofinfrastructureisinfastdevelopment.Higherrequirementsincludingwatersupplysysteminthecityareaoftheproposed.FrequencyconversionconstantpressurecontrolsystemiswidelyusedinwatersupplysystemsinresidentialareainChina,thetraditionalcontrolmethodhasthedisadvantagesoflowaccuracy,highenergyconsumptioncontrol,MultiplecirculationpumpfrequencyconversionconstantpressurewatersupplysystembasedonPLCcontrolanddesignofthestudy,theuseofprogrammablelogiccontroller,transducerandpressuretransducerdevices,finish.Logiccontrol,frequencycontrolanddatasamplingfunction,allowingthesystemtoachieveautomaticcontrol,toachievethepurposeofsavingenergy,improvethequalityofwatersupplysystems.Accordingtothedesignofresidentialwatersupplyrequirements,designasetofresidentialwatertowerwaterlevelbasedonPLCcontrolsystem.Thesystemmainlyconsistsofaprogrammablecontroller(PLC),frequencyconverter,liquidlevelswitch,pressuresensorandpumpetc..Throughthedesignofafrequencyconvertertocontrolthreepumpstart-stopandspeed.Theswitchingbetweentheworkingfrequencyandfrequencyoperation,softstartandwaterpumpwatersupplypump.Throughthepressuresensortodetectthepressureofwatersupplynetworks,andthehydraulicpressuresignalmeasuredfeedbackPLC,comparedwithagivenvalue,afterPIDoperation,theoperationresulttotheinverter,soastorealizethecontrolofIIIoutputvoltageandfrequencyoftheinverter,theoutputvoltageandfrequencyconverterthroughthecontrol,tochangethewatersupplythewaterpumpmotorspeed,andthenchangethewatersupply.Whenafireoccurs,sothatthethreepumpsinthepowerfrequencyoperationstateatthesametime,tomeetthefirewater.Thesystemrealizestheautomaticswitchingbetweenhighpressurewatersupplyresidentsofthewaterbottompressureofnormalwatersupplyandfireoccurswhenbothwaterandtheir.Atthesametimetorealizethefunctionofwaterlevelautomaticalarm.Thedesignofthesystemnotonlyrealizestheautomaticcontrolofwatersupplyprocess,butalsototheenergysavingbenefits.Keywords:ProgrammableControllerPLCconstant-pressurefrequencyIV目录摘要.................................................................................................................................IAbstract..............................................................................................................................II第一章绪论......................................................................................................................11.1课题产生的背景及意义......................................................................................11.2变频恒压供水的国内外研究现状......................................................................11.3变频恒压供水的特点及应用..............................................................................31.4本设计的主要研究内容......................................................................................41.5系统设计的理论分析及方案的确定及变频恒压供水系统的理论分析..........41.5.1变频恒压供水系统的基本原理...............................................................41.5.2控制系统的节能原理...............................................................................51.6变频恒压供水系统控制方案的确定..................................................................61.6.1几种控制方案的比较及其确定...............................................................61.6.2变频恒压供水系统的组成及原理图.......................................................71.6.3系统中水泵切换条件分析.......................................................................9第二章变频恒压供水系统的硬件设计.........................................................................132.1可编程控制器PLC的选型...............................................................................132.1.1PLC简介.................................................................................................132.1.2PLC的基本组成.....................................................................................142.1.3PLC的工作过程.....................................................................................152.1.4可编程控制器（PLC）及外接模块的选型..........................................172.2变频器的选型....................................................................................................182.2.1变频器简介.............................................................................................182.2.2变频器的选型.........................................................