毕业论文外文翻译-基于DS18B20分组方式温度测试系统设计.docx

毕业论文外文翻译-基于DS18B20分组方式温度测试系统设计.docx

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外文原文：

ADesignoftheTemperatureTestSystemBasedonGroupingDS18B20

LIPingZHOUYucaiXiangjunZENGYANGTing-fangChangshaUniversityofScienceandTechnology,Changsha410077,Hunan,P.R.China.

E-Mail:

0702liping@

Abstract-AlltheDS18B20sensors,usedforthemultipointtesttemperature,areconnectedwithMCUononeofIObus,andtemperaturedataarecollectedbyturns.Ifthesystemhasalargeamountofsensors,thetimeofMCUusedinprocessingthetemperaturedataisobviouslyprolonged,sothecycleofalternatetestgetslonger.Inthispaper,anewmethodthatDS18B20arerationallygroupedispresented,andsomemeasuresaretakeninsoftware;asaresult,thespeedofalternatetestadvancesdistinctly.

Keywords-DS18B20Group,temperaturetest,timespentonthealternatetest.

I.INTRODUCTION

Asthesimplestructure,convenientinstallment,lowlossandwiderangeoftemperaturetest,DS18B20temperaturetestsensorsareappliedtothefieldswhichneedthemultipointtemperaturetest,suchasthechemicalindustry,thegrain,theenvironmentsupervisionandsoon.BecauseoftheadoptionofonebusintheDS18B20multipointtemperaturetestsystem,allDS18B20arehungononebus,andthenthetemperatureconversionvalueofeachtestpointisreadbyturns.Astheconversionvaluemustbereadafterreading-pinstatefor8times,andpositionandstoredatamustbemoved,sotimespendmuchinreadingonepointofthedatasystembyeverytime.Ifthetemperaturetestsystemislarge-scaled,thesystemlosscausedbyitisrathermuch,andthenthealternatetestspeedofthesystemdecreasesobviously,whichinfluencestheefficiencyofthemultipointtemperaturetestsystemseriously.Inthispaper,DS18B20arehungonsomeI/ObusesbygroupingDS18B20evenly,andtheconversiontemperaturedataisobtainedbyreadingthestateofDS18B20,thenthesystemlossdecreasesandthealternatetestspeedincreasesobviously,whichwon’tinfluencetheprecisionandthereliabilityoftheconversion.Asetofmultipointtemperaturetestofartificialenvironmentlaboratoryisachievedinthispaper,whichincreasesthetestefficiencyoftheformersystem.

□Ⅱ.CHARACTERISTICSOFDS18B20

DS18B20isthesinglebusdigitaltemperaturesensorfromAmericanDallasCompany.DS18B20isconsistedofthe64figuresROMengravedbylaser,thetemperaturesensitivitycomponent,non-volatiletemperaturealarmstrigger（Device

THandTL）.DS18B20communicateswiththemicroprocessorbythesinglebusportandthetestrangeofDS18B20isfrom-55centigradeto+125centigrade,andtheincrementalvalueis0.5centigrade.Thetemperaturecanbechangedintofigureswithin720msandeachDS18B20hasthesole64figuresserialnumber.ThespecificcontentisrevealedasFig1:

Therearetwo8figuresstorages（No.0andNo.1）forstoringtemperaturevalueinDS18B20.No.0storagestorescomplementofthetemperaturevalue,andNo.1storessymbolsofthetemperaturevalue.Theusercandefinenon-volatiletemperaturealarmssetsanddistinguishthealarmssearchorderandseekthecomponenttemperaturealarmsstateoutsidethescheduledlimit.Therearetwoalternativewaysofpowersupply:

Signalbushigh-levelborrowpowerisadopted,orthe+5vpowersupplyexternallyisadopteddirectly.

Fig1DS18B2064bitROM

Ⅲ.APPLICATIONTHEGROUPINGTESTMETHOD

ThispaperillustratesthegroupingmethodwiththeinterfaceofDS18B20and89C52.AssumingtheamountofthebusesonP1portis4andthetemperaturetestsystemneeds100DS18B20sensors,whichcanbedistributedequallytothe4I/Olines.Ifthenumberofsensorscannotbedividedbythenumberofbuseseven,thenumberdisparityofsensors

onbusesisnomorethanone,whichcanbehandledwhilereadingnumbers.Thepowerissuppliedexternally.OwningtothesynchronisticconversionineachDS18B20,theintensecurrentisneeded,andthesignalbuscannotbeusedforthepowersupply,otherwisethesystemcannotworkinorder.TheschematiccircuitisshownasFig2（theDS18B20signalbusesofthesamegrouparehungonsomebusesofP1port）.WhenreadandwritetheDS18B20,thestrictschedulemustbekept.FirstareversionpulseissenttoallDS18B20.Afterthereversion,SkipROMorderissenttoeachcircuit

simultaneouslyfromtheI/Oport,andtheconversionorderissent,thenallsensorsbegintransform.Aftertheconversion,MatchRomorderissenttoeachcircuitsimultaneously,and64bitsserialnumberissent.DS18B20isselectedforeachgroup,andScratchPaddataisread.Finallythedataistransformed.Thedataofserial-readistransformedintotheactualtemperaturevalue.OnealternatetestisfinishedaftertheDS18B20temperaturedataisreadcompletelybythecyclicalreadingfor25times.ThewholeflowchartisshownasFig3.

Fig3thediagramofcollectingtemper