毕业设计-基于PLC的液位控制系统设计.pdf

毕业设计-基于PLC的液位控制系统设计.pdf

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无无锡锡职职业业技技术术学学院院毕业实践任务书毕业实践任务书课题名称基于基于PLC的液位控制系统设计的液位控制系统设计指导教师职称指导教师职称专业名称生产自动化生产自动化班级学生姓名学号实习单位课题需要完成的任务：

课题需要完成的任务：

利用信捷PLC设计液位控制系统，完成如下任务：

1、通过触摸屏、可变程序控制器变频器（PLC）、压力传感器、配电装置以及水泵实现液位控制系统的设计2、确定控制方案，选择PLC型号，定义输入/输出，画出PLC端子接线图。

3、进行软件编程、完成控制梯形图并完成调试。

课题计划：

课题计划：

10年年2月月26日日-10年年3月月10日日确定毕业设计课题确定毕业设计课题10年年3月月11日日-10年年3月月22日日调查参观、完成调研报告调查参观、完成调研报告10年年3月月22日日-10年年3月月31日日确定方案，完成方案论证确定方案，完成方案论证10年年4月月1日日-10年年4月月20日日设计电路，编制程序，完成论文设计电路，编制程序，完成论文计划答辩时间：

计划答辩时间：

10年年4月月21日日-10年年4月月30日日自动控制技术系自动控制技术系系（部、分院）系（部、分院）2010年年4月月26日日无锡职业技术学院无锡职业技术学院毕业设计说明书（英文翻译）毕业设计说明书（英文翻译）1PLCs-Past,PresentandFutureEveryoneknowstheresonlyoneconstantinthetechnologyworld,andthatschange.ThisisespeciallyevidentintheevolutionofProgrammableLogicControllers（PLC）andtheirvariedapplications.Fromtheirintroductionmorethan30yearsago,PLCshavebecomethecornerstoneofhundredsofthousandsofcontrolsystemsinawiderangeofindustries.Atheart,thePLCisanindustrializedcomputerprogrammedwithhighlyspecializedlanguages,anditcontinuestobenefitfromtechnologicaladvancesinthecomputerandinformationtechnologyworlds.Themostprominentofwhichisminiaturizationandcommunications.TheTheShrinkingShrinkingPLCPLCWhenthePLCwasfirstintroduced,itssizewasamajorimprovement-relativetothehundredsofhard-wiredrelaysandtimersitreplaced.AtypicalunithousingaCPUandI/Owasroughlythesizeofa19televisionset.Throughthe1980sandearly1990s,modularPLCscontinuedtoshrinkinfootprintwhileincreasingincapabilitiesandperformance（seeDiagram1fortypicalmodularPLCconfiguration）.Inrecentyears,smallerPLCshavebeenintroducedinthenanoandmicroclassesthatofferfeaturespreviouslyfoundonlyinlargerPLCs.ThishasmadespecifyingalargerPLCjustforadditionalfeaturesorperformance,andnotincreasedI/Ocount,unnecessary,aseventhoseinthenanoclassarecapableofEthernetcommunication,motioncontrol,on-boardPIDwithautotune,remoteconnectivityandmore.PLCsarealsonowwell-equippedtoreplacestand-aloneprocesscontrollersinmanyapplications,duetotheirabilitytoperformfunctionsofmotioncontrol,dataacquisition,RTU（remotetelemetryunit）andevensomeintegratedHMI（humanmachineinterface）functions.Previously,thesefunctionsoftenrequiredtheirownpurpose-builtcontrollersandsoftware,plusaseparatePLCforthediscretecontrolandinterlocking.TheTheGreatGreatCommunicatorCommunicatorPossiblythemostsignificantchangeinrecentyearsliesinthecommunicationsarena.Inthe1970sModiconintroductionofModbuscommunicationsprotocolallowedPLCstocommunicateoverstandardcabling.ThistranslatestoanabilitytoplacePLCsincloserproximitytorealworlddevicesandcommunicatebacktoothersystemcontrolsinamainpanel.Inthepast30yearswehaveseenliterallyhundredsofproprietaryandstandardprotocolsdeveloped,eachwiththeirownuniqueadvantages.TodaysPLCshavetobe无锡职业技术学院无锡职业技术学院毕业设计说明书（英文翻译）毕业设计说明书（英文翻译）2datacompilersandinformationgateways.Theyhavetointerfacewithbarcodescannersandprinters,aswellastemperatureandanalogsensors.Theyneedmultipleprotocolsupporttobeabletoconnectwithotherdevicesintheprocess.Andfurthermore,theyneedallthesecapabilitieswhileremainingcost-effectiveandsimpletoprogram.AnotherprimarydevelopmentthathasliterallyrevolutionizedthewayPLCsareprogrammed,communicatewitheachotherandinterfacewithPCsforHMI,SCADAorDCSapplications,camefromthecomputingworld.UseofEthernetcommunicationsontheplantfloorhasdoubledinthepastfiveyears.Whileserialcommunicationsremainpopularandreliable,Ethernetisfastbecomingthecommunicationsmediaofchoicewithadvantagesthatsimplycantbeignored,suchas:

*Networkspeed.*Easeofusewhenitcomestothesetupandwiring.*Availabilityofoff-the-shelfnetworkingcomponents.*Built-incommunicationssetups.IntegratedIntegratedMotionMotionControlControlAnotherresponsibilitythePLChasbeentaskedwithismotioncontrol.Fromsimpleopen-looptomulti-axisapplications,thetrendhasbeentointegratethisfeatureintoPLChardwareandsoftware.Therearemanyapplicationsthatrequireaccuratecontrolatafastpace,butnotexactprecisionatblazingspeeds.Theseareapplicationswherethestand-alonePLCworkswell.ManynanoandmicroPLCsareavailablewithhigh-speedcountingcapabilitiesandhigh-frequencypulseoutputsbuiltintothecontroller,makingthemaviablesolutionforopen-loopcontrol.Theonecaveatisthatthecontrollerdoesnotknowthepositionoftheoutputdeviceduringthecontrolsequence.Ontheotherhand,itsmainadvantageiscost.Evensimplemotioncontrolhadpreviouslyrequiredanexpensiveoptionmodule,andattimeswasrestrictedtomoresophisticatedcontrolplatformsinordertomeetsystemrequirements.Moresoph