基于单片机控制温湿度的系统外文及翻译.docx

基于单片机控制温湿度的系统外文及翻译.docx

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基于单片机控制温湿度的系统外文及翻译

NewEnvironmentParametersMonitoringAndControlSystemForGreenhouseBasedOnMaster-slaveDistributed

Abstract--Accordingtotheactualneedofmonitoringandcontrolofgreenhouseenvironmentparametersinruralareas,amaster-slavedistributedmeasurementandcontrolsystemisdesigned,inwhichPCistakenasthehost.ThesystemconsistsofPC,soilmoisturemeasurementandcontrolmodule,temperatureandhumidity,andCO2monitoringandcontrolmodule.Inthesystem,PChaslargeamountofdatastoragewhichiseasytomakeuseoffuzzycontrolexpertsystem,configurationsoftware-KingViewisusedtodevelopsoftwareforPC,bywhichthedevelopmentcycleisshortenandafriendlyhuman-computerinteractionisprovided.EachmonitoringandcontrolmoduleconsistsofSTC12seriesofmicrocontrollers,sensors,relaysetc.Differentmodulesareselectbasedontheneedifsystemtoachievecontrolgreenhouseinpartitionandblock.

I.INTRODUCTION

Tomodernindooragriculture,theautomaticmeasurementandcontrolofenvironmentparametersisthekeytoachievecropyieldandqualityofgreenhouse.Inrecentyears,facilitiesagriculturedevelopsvigorouslyinourcountry,matchedwithit,themonitoringandcontrolinstrumentofgreenhousehavealsomadecertaindevelopment.Afternearly10yearsofunremittinghardwork,ourresearchteamofmeasurementandcontrolsystemofagricultureenvironmentparameters,designedanintelligentmeasurementandcontrolsystemofdistributioncombinedofgreenhousewhichcanbepopularizedinthevastruralareas.Thissystemismainlycontroloftemperature,humidity,CO2concentration,soilmoistureandilluminationofgreenhouse.OFSCM,asthedatastorageissmall,displayinterfaceissingle,amountofinformationislimited,butitscapabilitypriceratioishigh,soitisusedasafrontunitofdataacquisitionandcontrol;andofPC,ithasalargeamountofdatastorage,richsoftware,convenienthuman-computerinteraction,andsoon.Ifweuseoutdatedandlow-pricedPC,takingthePCastheuppermachine,takingthedifferentfunctioncontrolmodulescomposedofmultiplemicrocomputersasthelowermachines,thenamaster-slavedistributedandintelligentcontrolsystembasesonmicrocomputerismadeup,bywhichbothbettermonitoringandcontrol,displayanddatacollectionormanagementareachieved,butalsolowercostofsystemisgetaccordingtotheactualneed.

IISYSTEMSTRUCTUREANDPRINCIPLE

Themostmarkedfeatureofthedistributioncombinedandintelligentcontrolsystemgreenhouseisthatofincorporatingwithdataacquisition,controlandmanagementasawhole,modulecombination,simplestructure,convenienthuman-computerinteraction,andusingtechnologyofintelligentexpertfuzzycontrol,whichcanadapttoavarietyofcropmanagementcontrolingreenhouse.ThebasicstructureofthesystemisshowninFig.1.

Thestructureofthedistributedsystemiscomposedoftwolayers:

theupperandlower.Inthetop-pricePCistakenasthehosttomakesystemmanagementandexpertsfuzzyoperationinintelligent,andtoprovideafriendlyhuman-computerinterface,andtorealizetheunitedmonitoringandmanagementofgreenhouse;theloweriscomposedofaseriesofmodulesofdifferentfunction,andineachmodule,asinglechipofAT89Cisadoptedasthelowermachine,RS485isusedtocommunicatePCwithallAT89C,andthenthecollection,processingandcontrolofthegreenhouseparametersisachieved.Eachfunctionmoduleiscompletelyisolatedinelectrical,anyfailureonthenoduledoesnotproduceanyeffectonothermodules.Thesystemcollectsseparatelywaysofenvironmentinformationthrougheachmonitoringandcontrolmodule,andsendsittohostPCthroughtheRS485interface.AndinthePCconfigurationcontrolsystem,theacquiredparametersarecomparedwiththevaluesofsetting,thenaccordingtoavarietyofexpertintelligentfuzzycontrolsystemofcropsatdifferentgrowthstages,thefuzzycontrolinstructionsontheenvironmenttemperature,humidity,CO2concentration,soilwatercontentandthecorrespondingoperationinstructionsoralarmaregiven.

ThesystemisappliedinruralgreenhousesinQinhuangdao.Usuallyat1/4nearEastandWestendinagreenhouse,andattheheightof1.5mfromthegroundinthemiddleinthenorthernhalf（nearthewetcurtain）andthesouthernhalf（nearthefan）,amoduleofairtemperatureandhumidity,CO2concentrationandamoduleofsoilmoisturecontentareset;amoduleofsoilmoisturecontentwillbeaddedinthemiddleofthegreenhouseaccordingtotheactualcondition;attheheightof1.5minthemainentrance,awatertankisset,ofwhichthesolenoidofdriptubeshouldbesetbasedontheneedandcontrolledbymoduleofsoilmoisturecontent;andthePCisplacedinthemainentrancetothegreenhouse.

III.HARDWAREDESIGN

A.TheCPandcommunicationsystem

Inthedistributedsystemofdataacquisitionandcontrol,asthemicrocontrolunitislimitedindatastorageandslowincalculatingofcomplexfunctions,soPCisusedandthemaster-slavemoduleisadoptedinthesystem,thatisasystemof,takingPCasthehostandtakingtheSCMsystemslocatedinthesceneasslave.

Inthisdistributedsystem,communicationisthekeytoit.Generally,theserialportofPCisstandardRS232,ofwhichtransmissiondistanceisshorter.Butinagriculturecontrolsystem.itscommunicationdistanceisoftensofmetersorseveralkilometers,soRS232/RS485converterisusedtoachievecommunicationbetweenthePCandSCM.Toreduceinvestment,bothconsideringtheuserconvenienceandfriendlyhuman-computerinteraction,low-pricePCofabove486andbelowPIVisadopted;andconsideringtheoperationofconfigurationsoftware,itisrequiredthatmemoryis64Moraboveandharddiskis10Gborabove.

B.Thecontrolmodulesoftemperatureandhumidity,illuminanceandCO2concentration

EachcontrolunitconsistsofSCM,sensors,signalprocessingcircuit,RS485interfaceandoutputcircuit.Thehardwarestructureofmoduleoftemperatureandhumidity,CO2concentrationisshowninFig.2.

CO2concentrationismeasuredbysensorbasedonNDIRtechnology,measurementisof0~2×103mol.Throughthesensor,controlsystem,bysoftwareofdigitalfilter,linearinterpolationandtemperaturecompensation,theCO2concentrationisoutputasdigitaladheredtoUARTprotocol,andthenisinputdirectlytotheSCM.

ThenewintelligentsensorofSHT11basedonCMOSenstechnologyischoseninthemeasurementoftemperatureandhumidity.InSHT11,thetemperatureandhumiditysensors,signalamplification,A/D,I2Cbusareallintegratedinachip;ithasfull-scalecalibration,second-linedigitaloutput,andhumiditymeasuringrangeof0~100%RH,temperaturemeasurementrangeof-40℃~+123.8℃,humiditymeasurementaccuracyof±3.0%RH,temperaturemeasurementaccuracyof±0.4℃,theresponsetimeof<4s.

TheilluminancesensorofJY1-TBQ-6ofsiliconphotovoltaicdetectionisusedLightmeasuring.Itsmeasurementrangeis0~200,000Lux;spectralrangeis400~700（nm）visiblelight;measurementerrorislessthan2%;outputis4~20mAor0~20mV;outputsignalcanbedirectlysendtotheA/DoftheSCMafterbeingamplifiedto0~4V.

ModulesaccepttheinstructionsformthetheUpper,andoutputviatheoutputcircuit.Theoutputcircuitconsistsofopticalisolation,thesignaldriverandtheoutputrelays.

C.Themeasurementandcontrolmodulesofsoilmoisture

Waterisapolarmedium,thedielectricconstantofthesoilcontainingwaterismainlydeterminedbythewater,whenwatercontentisdifferent,thewaveimpedanceisdifferent.Thesoilmoistureismeasuredbystandingwaveradiomethodinthissystem.

BasedonthetheoryofEngineeringElectromagneticField,forlossymedium,theelectromagneticwaveimpedanceasfollows:

Z0=√μ/ε（1+jλ/（ωε））

Whereμismediumpermeability,andμofsoilisμ≈μ0isthevacuumpermeability;εismediumdielectricconstant;λismediumconductivity;ωiselectromagneticwavefrequency.

Intheverylowaudio（<2000Hz）,thelosstangentofdrysoildielectricisλ/ωε≈0.07,ifyouchoosethefrequencyofthesignalsourceatabove20MHz.then,ε≈ε∞,theimaginarypartofthesoilwaveimpedanceisneglect,onlytherealpart,whichamountstoapureresistance.

Soilmoisturesensorconsistsof100MHzsignalsource,acoaxialtransmissionlineanda4-pinstainlessprobe.Theelectromagneticwavesofsignaltransmittotheprobealongthelines.Astheprobeimpedanceandlineimpedancearedifferent,thesuperimpositionofincidentwavesandreflectedwavesformsastandingwaves.

Takingthecoaxialtransmissionlineasalosslessuniformline,waveimpedanceisZ0,Zlistheloadimpedance.

Thenthereflectedcoefficientofvoltagewaveattheprobeis:

Γ=（ZL-Z0）/（ZL+Z0）

Choosingthelengthoftransmissionlineisl=λ/4,themaximumandminimumofbothendsofthelineareUmaxandUmin,Thenthestandingwaveradiointhelinecanbeexpressedas:

S=Umax/Umin=（1-|Γ|）/（1+|Γ|）

Intheway,thesoilmoistureradiocanbemeasuredbymeasuringthestandingwaverateoftransmissionline.

AsshowninFig.3.,soilmoisturemoduleconsistsofsensorsandcontrollers,thesensorsaresubordinatedtocontrollers,controllerscanbeomittedwithouttheneedofirrigationingreenhouse.

Tosimplifythecontrol,irrigationtechnologyofnode-typeinpartitionisadoptedinthecontrolsoilmoistureinthissystem.Toacertainextent,theparametersofupperandlowerthegroundcanbedecoupledbyadoptingthistechnology.

IVCONTROLSYSTEMPROGRAMMING

ThesoftwareofPCisdevelopedbyKingView6.51ofBeijing-controlledAsia.Thisconfigurationsoftwarehashighreliability,shorterdevelopmentcycle,perfectcapabilityofgraphicalinterfacegeneration,andfriendlyhuman-computerinteraction;andcancreatedynamicimagesandchartsinaccordance