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():,AD7746,,:;;;-:TH89:B:100429134(2008)03200012030,,,AD7746ADI(Ca2pacitance-to-DigitalConverter,CDC),,/ADC,AD774611.1,11lwd,[1],:C=0mrlwd(1)0=8.8510-12Fm-1mr,,,H-B[2],:mr=[w+(1-)p]2(2)wp,,,2.3,80,,1.2-AD7746[34]2-ADCCINCREFUINUREF,CINT,01,,01(UIN)(UREF),1,0,:,,1982,;::25706112008223PETROLEUMINSTRUMENTS2-ADCAD7746-ADC,UIN,CxCIN,3,Cx,CxCREF3AD7746,:-,,,/(CAPDAC),,,,,I2C,4,4AD7746,-CAPDAC(+)CAPDAC(-)/,Cin(+)Cin(-),,EXC1EXC2,I2CCDCAD7746,/4pF,017pF,(21bit)(4fF)(0.01%),25P89LPC932A1F,80C51Flash,,24,680C51512EEPROM,I2C,AD7746[5],OCMJ48CLCD,,RS485,5,,3,,030%,105010,,,EEPROM,1050,2PETROLEUMINSTRUMENTS2008060%30%,1%11/%//%/%016.400413.53.7-0.3822.18.10.11233.511.6-0.41632.115.7-0.32035.520.10.12449.023.3-0.72811.728.50.54AD7746,,,AD7746,[1],,.[J].,2007,21(2)[2],,.[J].,2004,28(5)[3]ADI.[J].,2006,(3)[4]AnalogDevices,Inc.24-BitCapacitance-to-DigitalConverterwithTemperatureSensorAD7745/AD7746[EB/OL].2005.05[5]NXPSemiconductors.P89LPC932A18-bitmicrocontrollerwithacceleratedtwo-clock80C51core[EB/OL].2007.03(:2008-01-22:)32008223:ABSTRACTSVol.22No.3Jun.2008ZhangBo,LiuRunhuaandChenCan.Designofcrudewatercutmeterbasedonthecapacitivesensor.PI,2008,22(3):13Anewtypeofcrudeoilswatercutmeterisdesignedbasedonthecapacitivewatercutsensor,whilethenewca2pacitance2to2digitalconverterAD7746isappliedtomeasurethesmallcapacitanceofsensorwithhighprecision.Thispa2perpresentsthemeasurementprincipleandmaindesignofthemeter.Experimentalresultsforthemixtureoftapwateranddieseloilinthelaboratoryshowthatthemetercanmeasurethewatercutwithhighprecision.Keywords:capacitance2to2digitalconverter;watercut;capacitivesensor;sigma2deltatechniqueLiTaoLiuYichengandZhuZhengping.DesignofanIntelligentdilativetesterbasedonthesingle2chipmicro2computer.PI,2008,22(3):45Anintelligentdilatationtestinstrumentbasedonthesingle2chipmicrocomputerisdesignedtoobjectivelyandtrulyevaluateshaledilatancy.Inthepaperthestructureofhardwareandsoftwareofthesystemispresentedindetail.Thetestingprincipleandsystemframeworkareintroducedinthehardwaredesignandtheproceduralflowchartisgiveninthesoftware.Keywords:single2chipmicrocomputer;pulsewidth;modulationdilativerate;preventdilativerate;untouchedLiuYong,ShaoGaoping,LuQingandLiuJiayong.Designofthegeneralmaintenancesystemforwelllogginginstruments.PI,2008,22(3):68,11Thepaperintroducesamaintainingsystemforwelllogginginstruments,whichcanachieveparametersetting,oper2ationcontrol,anddatareceiving,processinganddisplayingthroughtheInstrumentBus.Thesystemhasfriendlyinter2face,whichmakesthecontrolandmaintenanceoflogginginstrumentsconvenient.Thesystemsoftwarecanbeupdatedandnewfunctionwillbeextended.ThissystemcansupportalltheloggingequipmentwhichisbasedonIB,itmakesthetestoflogginginstrumentsveryflexible.Keywords:logginginstrument;maintenancesystem;instrumentbusZhaoZhixue,HanYuan,BaiXiaojieandMengXiangguang.Developmentofdetectionequipmentoftherectifi2cationanddrivemoduleformeasurementwhiledrillingdownholetools.PI,2008,22(3):911Withtheconstantlydevelopmentofdrillingengineeringtechnologyinrecentyears,theresearchofthemeasurementwhiledrillingdownholetoolbecomesanewpopularfield.Rectificationmoduleandthedrivemodulearethemostimpor2tantpartsofthemeasurementwhiledrillingdownholetool,theentirereliabilityoftoolisraisedbytheirdetectinganddebuggingintheground.Thedevelopmentofdetectionequipmentoftherectificationanddrivemoduleforthemeasure2mentwhiledrillingdownholetoolisdescribed,itsheartisthecontrolsystemofthechipmicroprocessorSTC12C5410AD,andthepowersupplyandsignalscanbeentirelysimulated.Hardwareandsoftwaredesignofthede2tectionequipmentisemphasizedinthispaper,therectificationanddrivemodulearewellcheckedbytheexperiments.Keywords:chipmicroprocessor;measurementwhiledrillingdownholetool;rectificationanddrivemoduledetectione2quipmentMaoYurong.Designoftheintelligentpowerfactormonitor2compensationsystem.PI,2008,22(3):1213,17TheintelligentpowerfactorcompensationsystemisdesignedbasedonAT89S52.Thispapergivestheprincipleandrealizationmethodofpowerfactormonitorandcompensation.Thesystemiscomposedofthesamplecircuit,compensatecircuit,controlcircuitanddisplaycircuit.Thefeatureistomonitorthecircuitatfirstandthentoadjustthecompensa2tioncapacitortogainthegivenpowerfactor.Thedisplayofvoltage,current,frequencyandpowerfactorisrealizedbytheAT89S52,andADC0809andsomerelatedelectroniccomponent.Thesystemcompletelyrealizesthetestingonline,intelligentcomputing,tracingadjustment,displayingonlineetc.andthenitovercomesthedisadvantageofthetradition2alsystem.Keywords:powerfactor;capacitivecompensation;microcomputerVol.22No.3PETROLEUMINSTRUMENTS