What Is Data Acquisition Toolbox?

744 Pages·2007·4.05 MB·English

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.
FEDERALACQUISITION:ThisprovisionappliestoallacquisitionsoftheProgramandDocumentation
by,for,orthroughthefederalgovernmentoftheUnitedStates. ByacceptingdeliveryoftheProgramor
Documentation,thegovernmentherebyagreesthatthissoftwareordocumentationqualifiesascommercial
computersoftwareorcommercialcomputersoftwaredocumentationassuchtermsareusedordefined
inFAR12.212,DFARSPart227.72,andDFARS252.227-7014. Accordingly,thetermsandconditionsof
thisAgreementandonlythoserightsspecifiedinthisAgreement,shallpertaintoandgoverntheuse,
modification,reproduction,release,performance,display,anddisclosureoftheProgramandDocumentation
bythefederalgovernment(orotherentityacquiringfororthroughthefederalgovernment)andshall
supersedeanyconflictingcontractualtermsorconditions. IfthisLicensefailstomeetthegovernment’s
needsorisinconsistentinanyrespectwithfederalprocurementlaw,thegovernmentagreestoreturnthe
ProgramandDocumentation,unused,toTheMathWorks,Inc.
Trademarks
MATLAB,Simulink,Stateflow,HandleGraphics,Real-TimeWorkshop,SimBiology,
SimHydraulics, SimEvents, andxPCTargetBoxareregisteredtrademarksandThe
MathWorks, theL-shapedmembranelogo,EmbeddedMATLAB,andPolySpaceare
trademarksofTheMathWorks,Inc.
Otherproductorbrandnamesaretrademarksorregisteredtrademarksoftheirrespective
holders.
Patents
The MathWorks products are protected by one or more U.S. patents. Please see
www.mathworks.com/patentsformoreinformation.
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