熱電偶溫度監(jiān)測(cè)解決方案

ADIADuCM360熱電偶溫度監(jiān)測(cè)處理方案關(guān)鍵字：工業(yè)控制,溫度監(jiān)測(cè),數(shù)據(jù)采集ADI企業(yè)旳ADuCM360是全集成旳4kSPS24位數(shù)據(jù)采集系統(tǒng),集成了兩個(gè)高性能多路Sigma-Delta(Σ-Δ)ADC,32位ARMCortexM3?MCU和閃存/EE存儲(chǔ)器,能直接雙線和外接精密傳感器接口,并采用電池供電.模擬輸入/輸出,單端和全差分輸入,輸入范圍±6.64mV到±1.2V,可編程ADC輸出速率(4Hz到4kHz),可編程增益從1到128,RMS噪音為43nV@3.75Hz和180nV@50Hz,重要用于工業(yè)自動(dòng)化和過(guò)程控制,智能旳精密檢測(cè)系統(tǒng),4mA到20mA回路智能傳感器系統(tǒng),醫(yī)療設(shè)備和病人監(jiān)護(hù).本文簡(jiǎn)介了ADuCM360重要特性,方框圖,以及采用ADuCM360和外接熱電偶旳基于USB溫度監(jiān)測(cè)器特性,電路圖和材料清單與PCB布局圖.ADI

TheADuCM360isafullyintegrated,4kSPS,24-bitdataacqui-sitionsystemincorporatingdual,highperformancemulti-channelsigma-delta(Σ-Δ)analog-to-digitalconverters(ADCs),32-bitARMCortexM3?MCU,andFlash/EEmemoryonasinglechip.Thepartisdesignedfordirectinterfacingtoexternalprecisionsensorsinbothwiredandbatterypoweredapplications.

TheADuCM361containsallthefeaturesoftheADuCM360excepttheprimaryADC,ADC0isnotavailable–onlytheauxiliaryADC,ADC1isavailable.

Thedevicecontainsanon-chip32KHzoscillatorandaninternal16MHzhigh-frequencyoscillator.ThisclockisroutedthroughaprogrammableclockdividerfromwhichtheMCUcoreclockoperatingfrequencyisgenerated.Themaximumcoreclockspeedis16MHzandthisisnotlimitedbyoperatingvoltageortemperature.

ThemicrocontrollercoreisalowpowerCortex-M3corefromARM.Itisa32-bitRISCmachine,offeringupto20MIPSpeakperformance.TheCortex-M3MCUincorporatesaflexible11-channelDMAcontrollersupportingallwired(SPI,UART,I2C)communicationperipherals.128kBytesofnon-volatileFlash/EEand8kBytesofSRAMarealsointegratedon-chip.

TheAnalogsub-systemconsistsofdualADCseachconnectedtoaflexibleinputMUX.BothADCscanoperateinfullydifferentialandsingleendedmodes.Otheron-chipADCfeaturesincludedualprogrammableexcitationcurrentsources,burn-outcurrentsourcesandabiasvoltagegeneratorofAVDD_REG/2(900mV)tosetthecommon-modevoltageofaninputchannel.Alow-sideinternalgroundswitchisprovidedtoallowpoweringdownofabridgebetweenconversions.TheADCscontaintwoparallelfilters–aSinc3orSinc4inparallelwithaSinc2.TheSinc3orSinc4filterisforprecisionmeasurements.TheSinc2filterisforfastmeasurementsandfordetectionofstepchangesintheinputsignalThedevicealsocontainsalownoise,lowdriftinternalband-gapreferenceorcanbeconfiguredtoacceptupto2externalreferencesourcesinratiometricmeasurementconfigurations.Anoptiontobuffertheexternalreferenceinputsisalsoprovidedon-chip.Asingle-channelbufferedvoltageoutputDACisalsoprovidedonchip.TheADuCM360/ADuCM361alsointegratesarangeofon-chipperipheralswhichcanbeconfiguredundermicrocontrollersoftwarecontrolasrequiredintheapplication.TheseperipheralsincludeUART,I2CanddualSPISerialI/Ocommunicationcontrollers,19-PinGPIOPorts,2GeneralPurposeTimers,Wake-upTimerandSystemWatchdogTimer.A16-bitPWMwithsixoutputchannelsisalsoprovided.

TheADuCM360/ADuCM361isspecificallydesignedtooperateinbatterypoweredapplicationswherelowpoweroperationiscritical.Themicrocontrollercorecanbeconfiguredinanormaloperatingmodeconsuming290μA/MHz(includingFlash/SRAMIdd)resultinginanoverallsystemcurrentconsumptionof1mAwhenallperipheralsareactive.

Thepartcanalsobeconfiguredinanumberoflowpoweroperatingmodesunderdirectprogramcontrol,includinghibernatemode(internalwake-uptimeractive)consumingonly4μA.Inhibernatemode,peripheralssuchasexternalinterruptsortheinternalwakeuptimercanwakeupthedevice.Thisallowstheparttooperateinanultra-lowpoweroperatingmodeandstillrespondtoasynchronousexternalorperiodicevents.

On-chipfactoryfirmwaresupportsin-circuitserialdownloadviaaserialwireinterface(2-pinJTAGsystem)andUARTwhilenon-intrusiveemulationisalsosupportedviatheserialwireinterface.Thesefeaturesareincorporatedintoalow-costQuickStartDevelopmentSystemsupportingthisPrecisionAnalogMicrocontrollerfamily.

Thepartoperatesfromanexternal1.8Vto3.6Vvoltagesupplyandisspecifiedoveranindustrialtemperaturerangeof-40°Cto125℃.

TheADuCM360isafullyintegrated,4kSPS,24-bitdataacqui-sitionsystemincorporatingdual,highperformancemulti-channelsigma-delta(Σ-Δ)analog-to-digitalconverters(ADCs),32-bitARMCortexM3?MCU,andFlash/EEmemoryonasinglechip.Thepartisdesignedfordirectinterfacingtoexternalprecisionsensorsinbothwiredandbatterypoweredapplications.

TheADuCM361containsallthefeaturesoftheADuCM360excepttheprimaryADC,ADC0isnotavailable–onlytheauxiliaryADC,ADC1isavailable.

Thedevicecontainsanon-chip32KHzoscillatorandaninternal16MHzhigh-frequencyoscillator.ThisclockisroutedthroughaprogrammableclockdividerfromwhichtheMCUcoreclockoperatingfrequencyisgenerated.Themaximumcoreclockspeedis16MHzandthisisnotlimitedbyoperatingvoltageortemperature.

ThemicrocontrollercoreisalowpowerCortex-M3corefromARM.Itisa32-bitRISCmachine,offeringupto20MIPSpeakperformance.TheCortex-M3MCUincorporatesaflexible11-channelDMAcontrollersupportingallwired(SPI,UART,I2C)communicationperipherals.128kBytesofnon-volatileFlash/EEand8kBytesofSRAMarealsointegratedon-chip.

TheAnalogsub-systemconsistsofdualADCseachconnectedtoaflexibleinputMUX.BothADCscanoperateinfullydifferentialandsingleendedmodes.Otheron-chipADCfeaturesincludedualprogrammableexcitationcurrentsources,burn-outcurrentsourcesandabiasvoltagegeneratorofAVDD_REG/2(900mV)tosetthecommon-modevoltageofaninputchannel.Alow-sideinternalgroundswitchisprovidedtoallowpoweringdownofabridgebetweenconversions.TheADCscontaintwoparallelfilters–aSinc3orSinc4inparallelwithaSinc2.

TheSinc3orSinc4filterisforprecisionmeasurements.TheSinc2filterisforfastmeasurementsandfordetectionofstepchangesintheinputsignalThedevicealsocontainsalownoise,lowdriftinternalband-gapreferenceorcanbeconfiguredtoacceptupto2externalreferencesourcesinratiometricmeasurementconfigurations.Anoptiontobuffertheexternalreferenceinputsisalsoprovidedon-chip.Asingle-channelbufferedvoltageoutputDACisalsoprovidedonchip.TheADuCM360/ADuCM361alsointegratesarangeofon-chipperipheralswhichcanbeconfiguredundermicrocontrollersoftwarecontrolasrequiredintheapplication.TheseperipheralsincludeUART,I2CanddualSPISerialI/Ocommunicationcontrollers,19-PinGPIOPorts,2GeneralPurposeTimers,Wake-upTimerandSystemWatchdogTimer.A16-bitPWMwithsixoutputchannelsisalsoprovided.

TheADuCM360/ADuCM361isspecificallydesignedtooperateinbatterypoweredapplicationswherelowpoweroperationiscritical.Themicrocontrollercorecanbeconfiguredinanormaloperatingmodeconsuming290μA/MHz(includingFlash/SRAMIdd)resultinginanoverallsystemcurrentconsumptionof1mAwhenallperipheralsareactive.

Thepartcanalsobeconfiguredinanumberoflowpoweroperatingmodesunderdirectprogramcontrol,includinghibernatemode(internalwake-uptimeractive)consumingonly4μA.Inhibernatemode,peripheralssuchasexternalinterruptsortheinternalwakeuptimercanwakeupthedevice.Thisallowstheparttooperateinanultra-lowpoweroperatingmodeandstillrespondtoasynchronousexternalorperiodicevents.

On-chipfactoryfirmwaresupportsin-circuitserialdownloadviaaserialwireinterface(2-pinJTAGsystem)andUARTwhilenon-intrusiveemulationisalsosupportedviatheserialwireinterface.Thesefeaturesareincorporatedintoalow-costQuickStartDevelopmentSystemsupportingthisPrecisionAnalogMicrocontrollerfamily.

Thepartoperatesfromanexternal1.8Vto3.6Vvoltagesupplyandisspecifiedoveranindustrialtemperaturerangeof-40℃to125℃.

ADuCM360重要特性:

AnalogInput/Output

Dual(24-bit)ADCs(ADuCM360)

Single(24-bit)ADC(ADuCM361)

SingleEndedandfullyDifferentialinputs

ProgrammableADCoutputrate(4Hzto4kHz)

Simultaneous50Hz/60Hzrejection

50SPSContinuousConversionMode

16.67SPSSingleConversionMode

FlexibleinputMUXforinputchannelselectiontobothADCs

PrimaryandAuxiliary(24-bit)ADCchannel

6differentialor11Single-Endedinputchannels

4internalchannelsformonitoringDAC,Temperaturesensor,IOVDDandAVDD(ADC1only)

ProgrammableGain(1to128)

Selectableinputrange:±6.64mVto±1.2V

RMSnoise:43nV@3.75Hz,180nV@50Hz

Programmablesensorexcitationcurrentsources

10/50/100/150/200/250/300/400/500/600/800uAand1mAcurrentsourceoptions

On-chipprecisionVoltagereference(±4ppm/℃)

Single12-bitvoltageoutputDAC

NPNmodefor4-20mAloopapplications

Microcontroller

ARMCortex?M332-bitprocessorSerialWiredownloadanddebugInternalWatchcrystalforwakeuptimer16

MHzOscillatorwith8-wayProgrammableDivider

Memory128kBytesFlash/EEMemory,8kBytesSRAMIn-circuitdebug/downloadviaSerialWireandUART

PowerOperatesdirectlyfroma3.0VbatterySupplyRange:1.8Vto3.6V(max)

PowerConsumption

MCUActiveMode:Coreconsumes290μA/MHz

ActiveMode:1.0mA(Allperipheralsactive),coreoperatingat500KHz

Powerdownmode:4μA(WUTimerActive)

On-ChipPeripherals

UART,I2Cand2xSPISerialI/O

16-bitPWMController

19-PinMulti-FunctionGPIOPort

2GeneralPurposeTimers

Wake-upTimer/WatchdogTimer

Multi-ChannelDMAandInterruptController

PackageandTemperatureRange

48leadLFCSP(7mmx7mm)package–40℃to125℃

DevelopmentTools

Low-CostQuickStart?DevelopmentSystem

Third-PartyCompilerandemulatortoolSupport

MultipleFunctionalSafetyfeaturesforimproveddiagnostics

ADuCM360重要應(yīng)用:

Industrialautomationandprocesscontrol

Intelligent,precisionsensingsystems

4mAto20mAloop-poweredsmartsensorsystems

Medicaldevices,patientmonitoring

圖1.ADuCM360方框圖

采用ADuCM360精密模擬微控制器和外接熱電偶旳基于USB溫度監(jiān)測(cè)器

ThiscircuitusestheADuCM360/ADuCM361