整理英文传感器.docx

整理英文传感器.docx

《整理英文传感器.docx》由会员分享，可在线阅读，更多相关《整理英文传感器.docx（14页珍藏版）》请在冰豆网上搜索。

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