Data Acquisition Toolbox 2 User’s Guide How to Contact The MathWorks www.mathworks.com Web comp.soft-sys.matlab Newsgroup www.mathworks.com/contact_TS.html Technical Support [email protected] Productenhancementsuggestions [email protected] Bug reports [email protected] Documentationerrorreports [email protected] Orderstatus,licenserenewals,passcodes [email protected] Sales,pricing,andgeneralinformation 508-647-7000 (Phone) 508-647-7001 (Fax) The MathWorks, Inc. 3 Apple Hill Drive Natick, MA 01760-2098 Forcontactinformationaboutworldwideoffices,seetheMathWorksWebsite. DataAcquisitionToolboxUser’sGuide ©COPYRIGHT1999–2007byTheMathWorks,Inc. Thesoftwaredescribedinthisdocumentisfurnishedunderalicenseagreement.Thesoftwaremaybeused orcopiedonlyunderthetermsofthelicenseagreement. Nopartofthismanualmaybephotocopiedor reproducedinanyformwithoutpriorwrittenconsentfromTheMathWorks,Inc. 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Revision History May1999 Firstprinting NewforVersion1 November2000 Secondprinting RevisedforVersion2(Release12) June2001 Thirdprinting RevisedforVersion2.1(Release12.1) July2002 Onlineonly RevisedforVersion2.2(Release13) June2004 Onlineonly RevisedforVersion2.5(Release14) October2004 Onlineonly RevisedforVersion2.5.1(Release14SP1) March2005 Onlineonly RevisedforVersion2.6(Release14SP2) September2005 Onlineonly RevisedforVersion2.7(Release14SP3) October2005 Reprint Version2.1(Noticeupdated) November2005 Onlineonly RevisedforVersion2.8(Release14SP3+) March2006 Fourthprinting RevisedforVersion2.8.1(Release2006a) September2006 Onlineonly RevisedforVersion2.9(Release2006b) March2007 Onlineonly RevisedforVersion2.10(Release2007a) May2007 Fifthprinting MinorrevisionforVersion2.10 September2007 Onlineonly RevisedforVersion2.11(Release2007b) Contents Introduction to Data Acquisition 1 WhatIsDataAcquisitionToolbox? .................. 1-3 UnderstandingTheDataAcquisitionToolbox .......... 1-3 ExploringtheToolbox .............................. 1-4 SupportedHardware ............................... 1-4 AnatomyofaDataAcquisitionExperiment .......... 1-5 SystemSetup ..................................... 1-5 Calibration ....................................... 1-5 Trials ........................................... 1-6 DataAcquisitionSystem ........................... 1-7 Overview ........................................ 1-7 DataAcquisitionHardware ......................... 1-9 Sensors .......................................... 1-11 SignalConditioning ............................... 1-15 TheComputer .................................... 1-17 Software ......................................... 1-17 AnalogInputSubsystem ........................... 1-20 FunctionoftheAnalogInputSubsystem .............. 1-20 Sampling ........................................ 1-20 Quantization ..................................... 1-24 ChannelConfiguration ............................. 1-28 TransferringDatafromHardwaretoSystemMemory ... 1-31 MakingQualityMeasurements ...................... 1-34 WhatDoYouMeasure? ............................. 1-34 AccuracyandPrecision ............................. 1-34 Noise ........................................... 1-38 MatchingtheSensorRangeandA/DConverterRange ... 1-40 HowFastShouldaSignalBeSampled? ............... 1-40 GettingCommand-LineFunctionHelp .............. 1-45 v SelectedBibliography .............................. 1-46 Getting Started Using Data Acquisition Toolbox 2 InstallationInformation ........................... 2-2 BeforeYouInstall ................................. 2-2 ToolboxInstallation ................................ 2-2 HardwareandDriverInstallation .................... 2-3 ToolboxComponents ............................... 2-4 ToolboxComponents: InformationandInteraction ...... 2-4 M-FileFunctions .................................. 2-6 DataAcquisitionEngine ............................ 2-6 HardwareDriverAdaptor ........................... 2-9 SupportedHardware ............................... 2-9 UnsupportedHardware ............................ 2-11 AccessingYourHardware .......................... 2-12 ConnectingtoYourHardware ....................... 2-12 AcquiringData ................................... 2-12 OutputtingData .................................. 2-13 ReadingandWritingDigitalValues .................. 2-14 AcquiringDatainaLoop ........................... 2-16 UnderstandingtheToolboxCapabilities ............. 2-17 ContentsM-File ................................... 2-17 DocumentationExamples ........................... 2-17 QuickReferenceGuide ............................. 2-18 Demos .......................................... 2-18 ExaminingYourHardwareResources ............... 2-19 UsingthedaqhwinfoFunction ....................... 2-19 GeneralToolboxInformation ........................ 2-19 Adaptor-SpecificInformation ........................ 2-20 DeviceObjectInformation .......................... 2-21 GettingHelp ...................................... 2-23 vi Contents ThedaqhelpFunction .............................. 2-23 ThepropinfoFunction .............................. 2-23 Data Acquisition Session 3 UnderstandingtheDataAcquisitionSession ......... 3-2 Overview ........................................ 3-2 Example: TheDataAcquisitionSession ............... 3-3 CreatingaDeviceObject ........................... 3-5 UnderstandingDeviceObjects ....................... 3-5 CreatinganArrayofDeviceObjects .................. 3-6 WhereDoDeviceObjectsExist? ...................... 3-7 HardwareChannelsorLines ....................... 3-9 AddingChannelsandLines ......................... 3-9 MappingHardwareChannelIDstoMATLABIndices .... 3-10 ConfiguringandReturningProperties .............. 3-13 Overview ........................................ 3-13 PropertyTypes ................................... 3-13 ReturningPropertyNamesandPropertyValues ........ 3-15 ConfiguringPropertyValues ........................ 3-19 SpecifyingPropertyNames ......................... 3-21 DefaultPropertyValues ............................ 3-21 ThePropertyInspector ............................. 3-22 AcquiringandOutputtingData ..................... 3-23 DeviceObjectStates ............................... 3-23 StartingtheDeviceObject .......................... 3-24 LoggingorSendingData ........................... 3-24 StoppingtheDeviceObject .......................... 3-25 CleaningUp ....................................... 3-27 vii Getting Started with Analog Input 4 CreatinganAnalogInputObject .................... 4-3 AddingChannelstoanAnalogInputObject .......... 4-5 ChannelGroup ................................... 4-5 ReferencingIndividualHardwareChannels ............ 4-7 Example: AddingChannelsforaSoundCard ........... 4-8 ConfiguringAnalogInputProperties ................ 4-10 AnalogInput: BasicProperties ...................... 4-10 TheSamplingRate ................................ 4-11 TriggerTypes .................................... 4-12 TheSamplestoAcquireperTrigger .................. 4-13 AcquiringData .................................... 4-15 StartingtheAnalogInputObject ..................... 4-15 LoggingData ..................................... 4-15 StoppingtheAnalogInputObject .................... 4-16 AnalogInputExamples ............................ 4-17 BasicStepsforAcquiringData ...................... 4-17 AcquiringDatawithaSoundCard ................... 4-17 AcquiringDatawithaNationalInstrumentsBoard ..... 4-21 EvaluatingtheAnalogInputObjectStatus ........... 4-25 StatusProperties .................................. 4-25 TheDisplaySummary ............................. 4-26 Doing More with Analog Input 5 ConfiguringandSamplingInputChannels .......... 5-2 PropertiesAssociatedwithConfiguringandSamplingInput Channels ...................................... 5-2 InputChannelConfiguration ........................ 5-2 viii Contents SamplingRate .................................... 5-5 ChannelSkew .................................... 5-6 ManagingAcquiredData ........................... 5-8 AnalogInputDataManagementProperties ............ 5-8 PreviewingData .................................. 5-8 RulesforUsingpeekdata ........................... 5-9 ExtractingDatafromtheEngine ..................... 5-11 ReturningTimeInformation ........................ 5-16 ConfiguringAnalogInputTriggers .................. 5-19 AnalogInputTriggerProperties ..................... 5-19 DefiningaTrigger: TriggerTypesandConditions ....... 5-20 ExecutingtheTrigger .............................. 5-25 TriggerDelays .................................... 5-26 RepeatingTriggers ................................ 5-30 HowManyTriggersOccurred? ....................... 5-35 WhenDidtheTriggerOccur? ........................ 5-36 Device-SpecificHardwareTriggers ................... 5-37 EventsandCallbacks .............................. 5-45 UnderstandingEventsandCallbacks ................. 5-45 EventTypes ...................................... 5-45 RecordingandRetrievingEventInformation ........... 5-48 CreatingandExecutingCallbackFunctions ............ 5-52 Examples: UsingCallbackPropertiesandFunctions .... 5-54 LinearlyScalingtheData: EngineeringUnits ........ 5-57 AnalogInputEngineeringUnitsProperties ............ 5-57 Example: PerformingaLinearConversion ............. 5-59 LinearConversionwithAsymmetricData ............. 5-60 Analog Output 6 GettingStartedwithAnalogOutput ................. 6-2 CreatinganAnalogOutputObject ................... 6-2 AddingChannelstoanAnalogOutputObject .......... 6-3 ConfiguringAnalogOutputProperties ................ 6-5 ix OutputtingData .................................. 6-7 AnalogOutputExamples ........................... 6-9 EvaluatingtheAnalogOutputObjectStatus ........... 6-12 ManagingOutputData ............................. 6-16 TheAnalogOutputSubsystem ...................... 6-16 QueuingDatawithputdata ......................... 6-16 Example: QueuingDatawithputdata ................. 6-18 ConfiguringAnalogOutputTriggers ................ 6-20 AnalogOutputTriggerProperties .................... 6-20 DefiningaTrigger: TriggerTypes .................... 6-21 ExecutingtheTrigger .............................. 6-22 HowManyTriggersOccurred? ....................... 6-22 WhenDidtheTriggerOccur? ........................ 6-23 Device-SpecificHardwareTriggers ................... 6-24 EventsandCallbacks .............................. 6-26 UnderstandingEventsandCallbacks ................. 6-26 EventTypes ...................................... 6-26 RecordingandRetrievingEventInformation ........... 6-29 Examples: Using Callback Properties and Callback Functions ...................................... 6-32 LinearlyScalingtheData .......................... 6-35 EngineeringUnits ................................. 6-35 Example: PerformingaLinearConversion ............. 6-36 StartingMultipleDeviceObjects .................... 6-38 Digital Input/Output 7 DigitalI/OObjects ................................. 7-3 CreatingaDigitalI/OObject ........................ 7-3 TheParallelPort .................................. 7-4 AddingLinestoaDigitalI/OObject ................. 7-6 x Contents