PPT（測控）數(shù)據(jù)采集技術

數(shù)據(jù)采集技術北京中科泛華測控技術有限公司數(shù)據(jù)采集功能

模擬輸入/輸出數(shù)字輸入/輸出時鐘輸入/輸出ADCDACcntr/timerdigitalDAQBoardOnOff1-0插入式數(shù)據(jù)采集卡的優(yōu)越性靈活費用較低性能選擇范圍大大量的軟件工具可用利用PC技術數(shù)字化技術信號分類信號根據(jù)其所傳遞的有用信息進行分類信息狀態(tài)速率幅值形狀頻率SignalsAnalogDigitalOn-OffTimeDomainPulseTrainFrequencyDomainDConofft1-0-t0.985ttf數(shù)字信號開關信號連續(xù)脈沖信號Input:ReadanopticalencoderOutput:Generateasquarewave分辨率時鐘頻率Input:SenseaswitchclosureOutput:Closeavalve驅(qū)動程序的功能通道數(shù)DAQ卡需要考慮的指標onofft1-0-t數(shù)字信號調(diào)理LoadsRequiringACSwitchingorLargeCurrentFlowProductionMonitoringorProcessControlCommon-ModeVoltagesorHighVoltagesElectromechanicalRelaysorSolid-StateRelaysOpticalIsolationSolenoidsValvesMotorsHeatersLampsPumpsElectromechanicalRelaysorSolid-StateRelaysProximitySwitchesLimitSwitchesThermostatsManualSwitches數(shù)字I/O模擬信號時域信號VibrationSpeechSonar分辨率采樣率AC精度觸發(fā)濾波器TemperaturePressureFlowStrainDC精度頻域信號直流信號ECGBloodpressureSingle-shoteventsChromatograph分辨率采樣率AC和DC精度觸發(fā)DAQ卡需要考慮的指標參數(shù)0.985ttf模擬信號調(diào)理低電壓信號電流輸入/輸出RTDs和熱敏電阻熱電偶應變儀隔離放大噪聲濾波電流與電壓的轉(zhuǎn)換;隔離，放大，噪聲濾波隔離，放大，噪聲濾波冷端補償激勵電源隔離，放大，噪聲濾波激勵電壓全橋和半橋設置隔離，放大，噪聲濾波多功能I/ODemo變送器/傳感器

物理現(xiàn)象

傳感器溫度

熱電偶

RTD IC傳感器

熱敏電阻光 真空管光電傳感器聲 麥克風力和壓力

應變儀

壓電傳感器熱電偶價格較低，堅固可承受高溫可迅速感知溫度的快速變化需要作冷端補償電壓量很小

需要放大輸出非線性需要冷端補償RTDs精度比熱電偶高不需要冷端補償比熱電偶昂貴需要電流源非線性輸出，需要線性化2路RTDs接線，簡單，但要考慮接線電阻誤差3路和4路

RTD接線，消除了接線電阻誤差熱敏電阻需要電流源或電壓源激勵非線性化強烈，需要線性化敏感度高電阻高應變片需要電壓源需要橋式電路設置非線性化輸出，需要線性化DAQ卡的前端信號調(diào)理模塊SignalConditioningeXtensionsforInstrumentation

(SCXI)SCXI選擇傳感器和信號熱電偶RTDs熱敏電阻應變儀電壓信號

微伏，毫伏，伏電流信號

4—20mA,0—20mA數(shù)字信號信號調(diào)理多路復用放大隔離濾波傳感器激勵冷端補償SCXI的其它特性可擴展，最多到3,072通道緊湊，在7英寸空間可達384個通道靈活，可以和最新的采集卡，軟件，和計算機配合工作高速，和E系列的采集卡配合掃描速度達333KHz設置方便結(jié)構(gòu)開放DemoA/D分辨率Codewidth=smallestdetectablechangeinvoltage=AD的輸入范圍增益*2nn=#ofADCbits

16-bitADC3-bitADCAmplitudecodewidthTime02010012014040608010.009.757.506.255.003.752.501.250111110100011010001000A/D采樣率Nyquist

原理

采樣率>2倍的最高頻率AdequatelysampledAliasedduetoundersampling多通道采集采集模式通道設置掃描順序增益范圍單端/差分輸入單極/雙極連續(xù)掃描同步采樣間隔掃描Straingauge1Straingauge2Battery1Battery2TempPressureDemo實時系統(tǒng)集成總線RTSI

Real-TimeSystemsIntegrationBusRTSI在板卡之間連接時鐘和觸發(fā)信號完成數(shù)據(jù)采集的同步操作在DSP卡串行傳輸數(shù)據(jù)觸發(fā)軟件觸發(fā)STARTTRIG*InputofMIOBoardEdgeInitiatesAcquisitionTTLSignalLevelandSlopeofAnalogSignalInitiatesAcquisition

LevelandSlopeofAnalogSignalRetrievesAcquisition條件獲取(軟件)由AIBufferRead設定AIRead調(diào)用

AIBufferRead模擬觸發(fā)數(shù)字觸發(fā)Demo應用軟件接口軟件軟件LabVIEWLabWindows/CVIComponentWorksVisualBasicC/C++...PCI-MIO-16E-1DAQ卡NI-DAQ要求:可以所有采集卡的功能向下兼容通用的

API功能齊全的設置工具方便易用DAQ的軟件接口NI-DAQApplicationSoftwareDemo軟件開發(fā)平臺選擇VirtualBench

Ready-to-RunVirtualInstrumentsVirtualInstrumentsScopeDynamicsignalanalyzerArbitrarywaveformgeneratorFunctiongeneratorDMMDataloggerDemo軟件開發(fā)平臺GraphicalProgrammingVisualC++LabWindows/CVIVisualBasicGraphicalProgramming

LabVIEWEmpoweringtechnologyNaturalflowchartnotationEliminatessyntacticaldetailsReducesdevelopmenttimeRapidprototypingSelf-documentingIntuitiveandeasytolearnIdealforcodereusabilityModularityandhierarchyDemoWhatisMeasurementStudio?MeasurementHardwareWindowsVisualBasic

VisualC++InternetVisualizationAnalysisAcquisitionLabWindows/CVIMeasurementStudioMeasurementComponentsMeasurementStudio

ToolsforVisualC++CompilerintegrationIntellisenseClassWizardVisaGPIBAnalysisUI

ControlsUtilityClassesData

ObjectApplicationWizardMeasurementclassesAcquisitionAnalysisUserinterfacethroughActiveXUtilityclassesDataobjectsMeasurementStudio

ToolsforVisualBasicMeasurementandautomationActiveXcontrolsAnalysisUIDAQNetworkGPIBSerialLabWindows/CVIANSICStandardLanguageCompilerEditorDebuggerOpenSystem

Built-in

Instrumentation

LibrariesI/O

(GPIB,VXI,

DAQ,Serial,

IMAQ,etc)Analysi