整理英文传感器.docx
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整理英文传感器
毕业设计中英文
翻译
学生姓名:
学号:
微电子学
学院:
鲍爱达
专业:
指导教师:
2011年6月
ELECTRONICS’200422-24September,Sozopol,BULGARIA
MEASUREMENTOFTEMPERATUREANDHUMIDITYUSING
SHT11/71INTELLIGENTSENSOR
Assist.Prof.GrishaSpasov,PhD,BScNikolayKakanakov
DepartmentofComputerSystems,TechnicalUniversity–branchPlovdiv,25,“Tzanko
Djustabanov”Str.,4000Plovdiv,Bulgaria,+35932659576,e-mail:
gvs@tu-plovdiv.bg,
kakanak@tu-plovdiv.bg
Keywords:
temperatureandhumiditymeasurements,intelligentsensors,
distributedautomationandcontrol
Thepaperdiscussestheadvantagesofintelligentsensors.ItpresentsanSHT11/71temperature
andhumiditycombinedsensorfromSensirion.Thissensorisidealfordevelopingdistributed
embeddedsystemsformonitoringenvironmentalparameters.
AnexampleapplicationusingthissensorisaddedtopresentSHT11/71inrealworking
condition.Theapplicationisdistributedsystemformonitoringtemperatureandhumidity.Itusesa
microcontrollerwithintegratedwebservertoorganizethecommunicationandmanagementof
sensors.Thisapplicationisrealizedandtested.
1.INTRODUCTION
Measurementandcontroloftemperatureandrelativehumidityhassignificant
applianceinindustry,science,healthcareagricultureandcontrollingtechnological
processes.Thesetwoenvironmentalparametersstronglyinfluenceeachotherandit
iscriticalinsomeapplicationtomeasuretheminparallel.Usingmoderntechnologies
itispossibletocombinetemperaturemeasurementelement,humiditymeasurement
element,amplifier,ADC,digitalinterface,calibrationmemoryandCRCcalculation
logicinasinglechipwithverysmallsize[1,3].
Usingintelligentsensorsofthiskindcanshortenthedevelopmenttimeandcost.
IntegratingADCandamplifierintosensor’schipallowdeveloperstooptimizesensor
elementsforaccuracyandlong-termstability.Andthatisnotall–integratingdigital
interfacelogicsimplifiesconnectivityandmanagementofsensors.Theseadvantages
canreducewholetime-to-markettimeandevenprice[1,3].
InpresentedpaperweuseSHT11/71intelligentsensorfromSensirionasan
exampleandpresentitsadvantagesandmeasurementprocedures.Anexample
applicationisalsopresentedtodemonstrateitsworkinrealconditions.This
applicationisrealizedandtested.
2.INTELIGENTSENSORS–SHT11/71
SHT11/71isasinglechiprelativehumidityandtemperaturemultisensormodule
comprisingacalibrateddigitaloutput.Thedeviceincludesacapacitivepolymer
sensingelementforrelativehumidityandabandgaptemperaturesensor.Bothare
seamlesslycoupledtoa14bitADCandaserialinterfacecircuitonthesamechip.
Thisresultsinhighsignalquality,afastresponsetimeandinsensitivitytoexternal
disturbances(EMC).EachSHT11/71isindividuallycalibratedandcalibration
coefficientsareprogrammedintotheOTPmemory.The2-wireserialinterfaceand
internalvoltageregulationalloweasyandfastsystemintegration[1].
ELECTRONICS’200422-24September,Sozopol,BULGARIA
TheSHT11/71isshownonfig.1[1].
Combiningtemperatureandhumiditysensingelementsinsingleunitenables
precisedeterminationofdewpoint,withoutincurringerrorsduetotemperature
gradientsbetweenelements.Thesignalamplificationnearthesensorallowsthe
polymerlayerstobeoptimizednotforsignalstrengths,butratherforlong-term
stability.Performinganalog-to-digitalconversion“inplace”makesthesignal
extremelyinsensitivetonoise.Achecksumgeneratedbythechipitselfisusedfor
additionalreliability.Thecalibrationdataloadedonthechipmemoryguaranteesthat
humiditysensorshaveidenticalspecificationsandthustheyare100%replaceable
[1].
SomeoftheadvancedfunctionsoftheSHT11/71areavailabletroughthestatus
register.Someofthemare:
internalheatingelement;regulationofmeasurement
resolutiontooptimizeforprecisionorforfastresponse;End-Of-Battery(EOB)
detection(lowvoltagedetection).Statusregistersizeis8bitsbutonlyfourofthem
areused[1].
SHT11/71canbeconnecteddirectlytoanymicrocontrollerbymeansofthe
digital2-wireinterface.Thisinterfaceisoptimizedforsensorreadoutandpower
consumptionandisnotcompatiblewithI2Cinterfaces[1].(Seefig.2)
Twowiresareusedtotransferserialclock(SCK)anddata(DATA).TheSCKis
usedtosynchronizethecommunicationbetweenamicrocontrollerandthe
SHT11/71.Sincetheinterfaceconsistsoffullystaticlogicthereisnominimum
frequency.TheDATAtristatepinisusedtotransferdatainandoutofthemodule.It
changesafterthefallingedgeandisvalidontherisingedgeoftheSCK.Duringthe
transmissiontheDATAlinemustremainstablewhileSCKishigh[1].
Signalsoverthetwolinesduringanexampletransmissionareshownonfig.3[1].
ELECTRONICS’200422-24S