粮库温度检测报警系统本科毕业生外文文献翻译.docx

粮库温度检测报警系统本科毕业生外文文献翻译.docx

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粮库温度检测报警系统本科毕业生外文文献翻译

本科毕业生外文文献翻译

学生姓名：

指导教师：

所在学院：

信息技术学院

专业：

电气工程及其自动化

中国·

2012年5月

BasedonSCMmulti-functionaltemperaturetestingsystemdesign

Introduction

Withthedevelopmentofsocietyandthetechnologicalprogress,peoplepaymoreandmoreattentiontotheimportanceoftemperaturedetectionanddisplay.Temperaturedetectionandstatusdisplaytechnologyandequipmenthasbeenwidelyappliedinindustries,productsonthemarketemergeinendlessly.Temperaturetestingandalsograduallyadopttheautomaticcontroltechnologytorealizethemonitor.Thistopicisatemperaturetestingandstatusofthemonitoringsystem.

1Systemsolutions

ThissystemUSESthemonolithicintegratedcircuitAT89S52asthissystem.Thewholesystem,thehardwarecircuitincludingpowersupplycircuit,sensor,thetemperaturedisplaycircuitcircuit,upperalarmcircuit.Thealarmingcircuitcanbemeasuredinuppertemperaturerange,screamingvoicealarm.ThebasicprincipleforthetemperaturecontrolDSl8B20:

whenthetemperaturesignalacquisitiontoaftertemperaturesignalsenttohandle,AT89S52temperaturetoLCDscreen,SCMaccordingtoinitializetheuppertemperaturesetting,namely,ifthejudgementoftemperaturethanthehighesttemperaturecoolingfanisstarted,Ifthetemperatureislessthanthelowesttemperaturesettingonalarmdevice.

2Thesystemhardwaredesign

2.1AT89C51SCMareintroduced

TheAT89S52isalow-power,high-performanceCMOS8-bitmicrocomputerwith4KbytesofFlashProgrammableandErasableReadOnlyMemory（PEROM）and128bytesRAM.ThedeviceismanufacturedusingAtmel’shighdensitynonvolatilememorytechnologyandiscompatiblewiththeindustrystandardMCS-51™instructionsetandpinout.Thechipcombinesaversatile8-bitCPUwithFlashonamonolithicchip,theAtmelat89s52isapowerfulmicrocomputerwhichprovidesahighlyflexibleandcosteffectivesolutiontomanyembeddedcontrolapplications.

PinDescription:

VCCSupplyvoltage.

GNDGround.

Port0

Port0isan8-bitopendrainbidirectionalI/Oport.AsanoutputporteachpincansinkeightTTLinputs.Whenisarewrittentoport0pins,thepinscanbeusedashighimpedanceinputs.

Port0mayalsobeconfiguredtobethemultiplexedloworderaddress/databusduringaccessestoexternalprogramanddatamemory.InthismodeP0hasinternalpullups.

Port0alsoreceivesthecodebytesduringFlashprogramming,andoutputsthecodebytesduringprogramverification.Externalpullupsarerequiredduringprogramverification.

Port1

Port1isan8-bitbidirectionalI/Oportwithinternalpullups.ThePort1outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort1pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs.Asinputs,Port1pinsthatareexternallybeingpulledlowwillsourcecurrentbecauseoftheinternalpullups.

Port1alsoreceivesthelow-orderaddressbytesduringFlashprogrammingandverification.

Port2

Port2isan8-bitbidirectionalI/Oportwithinternalpullups.ThePort2outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort2pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs.Asinputs,Port2pinsthatareexternallybeingpulledlowwillsourcecurrentbecauseoftheinternalpullups.

Port2emitsthehigh-orderaddressbyteduringfetchesfromexternalprogrammemoryandduringaccessestoexternaldatamemorythatuse16-bitaddresses（MOVX@DPTR）.Inthisapplicationitusesstronginternalpull-upswhenemitting1s.Duringaccessestoexternaldatamemorythatuse8-bitaddresses（MOVX@RI）,Port2emitsthecontentsoftheP2SpecialFunctionRegister.

Port2alsoreceivesthehigh-orderaddressbitsandsomecontrolsignalsduringFlashprogrammingandverification.

Port3

Port3isan8-bitbidirectionalI/Oportwithinternalpullups.ThePort3outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort3pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs.Asinputs,Port3pinsthatareexternallybeingpulledlowwillsourcecurrentbecauseofthepullups.

Port3alsoservesthefunctionsofvariousspecialfeaturesoftheat89s52aslistedbelow:

Portpin

alternatefunctions

P3.0

rxd（serialinputport）

P3.1

txd（serialoutputport）

P3.2

^int0（externalinterrupt0）

P3.3

^int1（externalinterrupt1）

P3.4

t0（timer0externalinput）

P3.5

t1（timer1externalinput）

P3.6

^WR（externaldatamemorywritestrobe）

P3.7

^rd（externaldatamemoryreadstrobe）

Port3alsoreceivessomecontrolsignalsforFlashprogrammingandverification.

RST

Resetinput.Ahighonthispinfortwomachinecycleswhiletheoscillatorisrunningresetsthedevice.

ALE/PROG

AddressLatchEnableoutputpulseforlatchingthelowbyteoftheaddressduringaccessestoexternalmemory.Thispinisalsotheprogrampulseinput（PROG）duringFlashprogramming.

InnormaloperationALEisemittedataconstantrateof1/6theoscillatorfrequency,andmaybeusedforexternaltimingorclockingpurposes.Note,however,thatoneALEpulseisskippedduringeachaccesstoexternalDataMemory.

Ifdesired,ALEoperationcanbedisabledbysettingbit0ofSFRlocation8EH.Withthebitset,ALEisactiveonlyduringaMOVXorMOVCinstruction.Otherwise,thepinisweaklypulledhigh.SettingtheALE-disablebithasnoeffectifthemicrocontrollerisinexternalexecutionmode.

PSEN

ProgramStoreEnableisthereadstrobetoexternalprogrammemory.

Whentheat89s52isexecutingcodefromexternalprogrammemory,PSENisactivatedtwiceeachmachinecycle,exceptthattwoPSENactivationsareskippedduringeachaccesstoexternaldatamemory.

EA/VPP

ExternalAccessEnable.EAmustbestrappedtoGNDinordertoenablethedevicetofetchcodefromexternalprogrammemorylocationsstartingat0000HuptoFFFFH.Note,however,thatiflockbit1isprogrammed,EAwillbeinternallylatchedonreset.

EAshouldbestrappedtoVCCforinternalprogramexecutions.

Thispinalsoreceivesthe12-voltprogrammingenablevoltage（VPP）duringFlashprogramming,forpartsthatrequire12-voltVPP.

XTAL1

Inputtotheinvertingoscillatoramplifierandinputtotheinternalclockoperatingcircuit.

XTAL2

Outputfromtheinvertingoscillatoramplifier.

2.2DS18B20sensor

2.2.1TheintroductionofDS18B20

TheDS18B20DigitalThermometerprovides9to12-bit（configurable）temperaturereadingswhichindicatethetemperatureofthedevice.Informationissentto/fromtheDS18B20overa1-Wireinterface,sothatonlyonewire（andground）needstobeconnectedfromacentralmicroprocessortoaDS18B20.Powerforreading,writing,andperformingtemperatureconversionscanbederivedfromthedatalineitselfwithnoneedforanexternalpowersource.BecauseeachDS18B20containsauniquesiliconserialnumber,multipleDS18B20scanexistonthesame1-Wirebus.Thisallowsforplacingtemperaturesensorsinmanydifferentplaces.ApplicationswherethisfeatureisusefulincludeHVACenvironmentalcontrols,sensingtemperaturesinsidebuildings,equipmentormachinery,andprocessmonitoringandcontrol.

TheDS18B20hasfourmaindatacomponents:

1）64-bitlaserROM,2）temperaturesensor,3）nonvolatiletemperaturealarmtriggersTHandTL,and4）aconfigurationregister.Thedevicederivesitspowerfromthe1-Wirecommunicationlinebystoringenergyonaninternalcapacitorduringperiodsoftimewhenthesignallineishighandcontinuestooperateoffthispowersourceduringthelowtimesofthe1-Wirelineuntilitreturnshightoreplenishtheparasite（capacitor）supply.Asanalternative,theDS18B20mayalsobepoweredfromanexternal3V-5.5Vsupply.

CommunicationtotheDS18B20isviaa1-Wireport.Withthe1-Wireport,thememoryandcontrolfunctionswillnotbeavailablebeforetheROMfunctionprotocolhasbeenestablished.ThemastermustfirstprovideoneoffiveROMfunctioncommands:

1）ReadROM,2）MatchROM,3）SearchROM,4）SkipROM,or5）AlarmSearch.Thesecommandsoperateonthe64-bitlaserROMportionofeachdeviceandcansingleoutaspecificdeviceifmanyarepresentonthe1-Wirelineaswellasindicatetothebusmasterhowmanyandwhattypesofdevicesarepresent.AfteraROMfunctionsequencehasbeensuccessfullyexecuted,thememoryandcontrolfunctionsareaccessibleandthemastermaythenprovideanyoneofthesixmemoryandcontrolfunctioncommands.

TemperaturesensorDS1820memorybyahighspeedbufferpadtypeRAMandanonvolatileelectricallyerasableE2RAMcomposition,thelatterisstoredathightemperatureandlowtemperatureandthetriggerofTHandTL.Scratchpadmemoryhelpsinone-waycommunicationtoensuredataintegrity,dataisfirstwrittentoabuffermemory,whereitcanbereadback.Whendataischecked,copyscratchpadmemorycommandtosendthedatatothenon-volatileE2RAM.Thisprocessensuresthatthechangeofmemorywhilemaintainingdataintegrity.

2.2.2ThecharacteristicsofDSl820

●Theuniquesingleinterfacemode:

DS18B20isconnectedwiththemicroprocessoronlyneedsanexportlinecanrealizemicroprocessorwithDS18B20bidirectionalcommunication.

●Availabledatalinepowersupply,voltagerange:

+3and+5.5V.

●Temperaturerange:

-55to+125degreesc..Intrinsictemperaturemeasurementresolutionof0.5DEGc..

●Supportpointnetworkfunction,multipleDS18B20canbeconnectedinparallelinonlythreeonline,realizethemultipointtemperaturemeasurement

●Negativepressurecharacteristics,powerpolarityreverseconnection,thethermometerisnotduetoheatandburning,butnotnormalWork.

2.3LCD1602LCD

1602LCDmodulecanandmonolithicintegratedcircuitAT89C51directlyinterface.