機(jī)械外文翻譯--應(yīng)用于電氣系統(tǒng)的可編程序控制器.doc

本科畢業(yè)論文（設(shè)計(jì)）外文資料翻譯學(xué)生姓名：所在院系：機(jī)電學(xué)院所學(xué)專業(yè)：機(jī)電技術(shù)教育導(dǎo)師姓名：完成時(shí)間：Programmabledesignedforelectro-pneumaticsystemscontrollerAbstractThisprojectdealswiththestudyofelectro-pneumaticsystemsandTheprogrammablecontrollerthatprovidesaneffectiveandeasywaytoControlthesequenceofthepneumaticactuatorsmovementandthestatesofpneumaticsystem.Theprojectofaspecificcontrollerforpneumaticapplicationsjointhestudyofautomationdesignandthecontrolprocessingofpneumaticsystemswiththeelectronicdesignbasedonmicrocontrollerstoimplementtheresourcesofthecontroller.1.IntroductionTheautomationsystemsthatuseelectro-pneumatictechnologyareformedmainlybythreekindsofelements:actuatorsormotors,sensorsorbuttonsandcontrolelementslikevalves.Nowadays,mostofthecontrolelementsusedtoexecutethelogicofthesystemweresubstitutedbytheProgrammableLogicController(PLC).Sensorsandswitchesarepluggedasinputsandthedirectcntrolvalvesfortheactuatorsarepluggedasoutputs.Aninternalprogramexecutesallthelogicnecessarytothesequenceofthemovements,simulatesothercomponentslikecounter,timerandcontrolthestatusofthesystem.WiththeuseofthePLC,theprojectwinsagility,becauseitispossibletocreateandsimulatetheaystemasmanytimesasnended.therefore,timecanbesaved,riskofmistakesreducedandcomplexitycanbeincreasedusingthesameelements.AconventionalPLC,thisispossibletofindonthemarketfrommanycompanies,offersmanyresourcestocontrolnotonlypneumaticsystems,butallkindsofsystemthatuseselectricalcomonents.thePLCcanbeveryversatileandrobustbeappliedinmanykindsofapplicationintheindustryorevensecuritysystemandautomationofbuildings.Becauseofthosecharacteristics,insomeapplicationsthePLCofferstomuchresourcesthatarenotevenusedtocontrolthesystem,electro-pneumaticsystemisoneofthiskindofapplication.TheuseofPLC,especiallyforsmallSizesystems,canbeveryexpensivefortheautomationproject.Analterativeinthiscaseistocreateaspecificcontrollerthatcanoffertheexactlysizeandresourcesthattheprojectnends.thiscanbemadeusingmicrcontrollersasthebaseofthiscontroller.Thecontroller,basedonmicrocontroller,canbeveryspecificandadaptedtoonlyOnekindofmachineoritcanworkasagenericcontrollerthatcanbeprogrammed.AsausualPLCandworkwithlogicthatcanbechanged.Allthecharacteristicsdependonwhatisneededandhowmuchexperiencethedesignerhaswithdevelopinganelectroniccircuitandfirmwareformicrocontroller.Butthemainadvantageofdesignthecontrollerwiththemicrocontrolleristhatthedesignerhasthetotalknowledgeofhiscontroller,whichmakesitpossibletocontrolthesizeofthecontroller,changethecomplexityandtheapplicationofit.Itmeansthattheprojectgetsmoreindependencefromothercompanies,butatthesametimetheresponsibilityofthecontrolofthesystemstaysatthedesignerhands.2.Electro-pneumaticsystemOnautomationsystemonecanfindthreebasiccomponentsmentionedbefore,plusAlogiccircuitthatcontrolsthesystem.Anadequatetechniqueisneededtoprojectthelogiccircuitandintegrateallthenecessarycomponentstoexecutethesequenceofmovementsproperly.Forasimpledirectsequenceofmovementanintuitivemethodcanbeused1,5,butforindirectormorecomplexsequencestheintuitioncangenerateaverycomplicatedcircuitandsignalmistakes.Itisnecessarytouseanothermethodthatcansavetimeoftheproject,makeacleancircuit,caneliminateoccasionalsignaloverlappingandredundantcircuits.Thepresentedmethodiscalledstep-by-steporlgorithmic,itisvalidforpneumaticandelectro-pneumaticsystemsanditwasusedasabaseinthiswork.Themethodconsistsofdesigningthesystemsbasedonstandardcircuitsmadeforeachchangeonthestateoftheactuators,thesechangesarecalledsteps.Thefirstpartistodesignthosekindsofstandardcircuitsforeachstep,thenexttaskistolinkthestandardcircuitsandthelastpartistoconnectthecontrolelementsthatreceivesignalsfromsensors,switchesandthepreviousmovements,andgivetheairorelectricitytothesupplylinesofeachstep.InFigs.(1)and(2)thestandardcircuitsaredrawnforpneumaticandelectro-pneumaticsystem.Itispossibletoseetherelationswiththepreviousandthenextsteps.3.themethodappliedinsidethecontrollerTheresultofthemethodpresentedbeforeisasequenceofmovementsoftheactuatorthatiswelldefinedbystepas.Itmeansthateachchangeonthepositionoftheactuatorsisanewstateofthesystemandthetransitionbetweenstatesiscalldstep.Thestandardcircuitdescribedbeforehelpsthedesignertodefinethestatesofthesystemsandtodefinetheconditiontoeachchangebetweenthestates.Intheendofthedesign,thesystemisdefinedbyasequencethatneverchancesandstatesthathavetheinputsandtheoutputswelldefined.Theinputsaretheconditionforthetransitionandtheoutputsaretheresultofthetransition.Alltheconfigurationofthosestepsstaysinsideofthemicrocontrollerandisexecutedthesamewayitwasdesigned.Thesequenceofstringsareprogrammedinsidethecontrollerwith5bytes；eachstringhastheconfigurationofonestepoftheprocessTherearetwobytesfortheinputs,onebytefortheoutputsandtwomorefortheotherconfigurationsandauxiliaryfunctionsofthestep.Afterprogramming,thissequenceofstringsissavedinsideofanon-volatilMemoryofthemicrocontroller,sotheycanbereadandexecuted.ThecontrollertaskisnottoworkinthesamewayasaconventionalPLC,butthepurposeofitistobeanexampleofaversatilecontrollerthatisdesignforanspecificarea.AconventionalPLCprocessthecontrolofthesystemusingacyclewhereitmakesanimageoftheinputs,executealltheconditionsdefinedbytheconfigurationprogrammedinside,andthenupdatethestateoftheoutputs.Thiscontrollerworksinadifferentway,whereitreadtheconfigurationofthestep,waittheconditionofinputstobesatisfied,thenupdatethestateortheoutputsandafterthatjumptothenextstepandstarttheprocessagain.Itcangeneratesomelimitations,asthefactthatthiscontrollerca