基于单片机控制温湿度的系统外文及翻译Word文件下载.docx
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基于单片机控制温湿度的系统外文及翻译Word文件下载.docx
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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
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