Data Acquisition Toolbox

Returning Property Names and Property Values

Once the device object is created, you can use the set function to return all configurable properties to a variable or to the command line. Additionally, if a property has a finite set of string values, then set also returns these values. You can use the get function to return one or more properties and their current values to a variable or to the command line.

The syntax used to return common and channel/line properties is described below. The examples are based on the analog input object ai created for a sound card and containing two channels.

ai = analoginput('winsound');
addchannel(ai,1:2);

Common Properties

To return all configurable common property names and their possible values for a device object, you must supply the device object to set. For example, all configurable common properties for ai are shown below. The base properties are listed first, followed by the device-specific properties.

set(ai)
        BufferingConfig
        BufferingMode: [ {Auto} | Manual ]
        Channel
        ChannelSkew
        ChannelSkewMode: [ {None} ]
        ClockSource: [ {Internal} ]
        DataMissedAction
        InputOverRangeAction
        InputType: [ {AC-Coupled} ]
        LogFileName
        LoggingMode: [ Disk | {Memory} | Disk&Memory ]
        LogToDiskMode: [ {Overwrite} | Index ]
        ManualTriggerHwOn: [ {Start} | Trigger ]
        Name
        RuntimeErrorAction
        SampleRate
        SamplesAcquiredAction
        SamplesAcquiredActionCount
        SamplesPerTrigger
        StartAction
        StopAction
        Tag
        Timeout
        TimerAction
        TimerPeriod
        TriggerAction
        TriggerChannel
        TriggerCondition: [ {None} ]
        TriggerConditionValue
        TriggerDelay
        TriggerDelayUnits: [ {Seconds} | Samples ]
        TriggerRepeat
        TriggerType: [ Manual | {Immediate} | Software ]
        UserData

        WINSOUND specific properties:
        BitsPerSample
        StandardSampleRates: [ Off | {On} ]

To return all common properties and their current values for a device object, you must supply the device object to get. For example, all common properties for ai are shown below. The base properties are listed first, followed by the device-specific properties.

get(ai)
        BufferingConfig = [512 30]
        BufferingMode = Auto
        Channel = [2x1 aichannel]
        ChannelSkew = 0
        ChannelSkewMode = None
        ClockSource = Internal
        DataMissedAction = daqaction
        EventLog = []
        InitialTriggerTime = [0 0 0 0 0 0]
        InputOverRangeAction = 
        InputType = AC-Coupled
        LogFileName = logfile.daq
        Logging = Off
        LoggingMode = Memory
        LogToDiskMode = Overwrite
        ManualTriggerHwOn = Start
        Name = winsound0-AI
        Running = Off
        RuntimeErrorAction = daqaction
        SampleRate = 8000
        SamplesAcquired = 0
        SamplesAcquiredAction = 
        SamplesAcquiredActionCount = 1024
        SamplesAvailable = 0
        SamplesPerTrigger = 8000
        StartAction = 
        StopAction = 
        Tag = 
        Timeout = 1
        TimerAction = 
        TimerPeriod = 0.1
        TriggerAction = 
        TriggerChannel = [1x0 aichannel]
        TriggerCondition = None
        TriggerConditionValue = 0
        TriggerDelay = 0
        TriggerDelayUnits = Seconds
        TriggerRepeat = 0
        TriggersExecuted = 0
        TriggerType = Immediate
        Type = Analog Input
        UserData = []

        WINSOUND specific properties:
        BitsPerSample = 16
        StandardSampleRates = On

To display the current value for one property, you supply the property name to get.

get(ai,'SampleRate')
ans =
        8000

To display the current values for multiple properties, you include the property names as elements of a cell array.

get(ai,{'StandardSampleRates','Running'})
ans = 
    'On'    'Off'

You can also use the dot notation to display a single property value.

ai.TriggerType
ans =
Immediate

Channel and Line Properties

To return all configurable channel (line) property names and their possible values for a single channel (line) contained by a device object, you must use the Channel (Line) property. For example, to display the configurable channel properties for the first channel contained by ai

set(ai.Channel(1))
        ChannelName
        HwChannel
        InputRange
        SensorRange
        Units
        UnitsRange

All channel properties and their current values for the first channel contained by ai are shown below.

get(ai.Channel(1))
        ChannelName = Left
        HwChannel = 1
        Index = 1
        InputRange = [-1 1]
        NativeOffset = 1.5259e-005
        NativeScaling = 3.0518e-005
        Parent = [1x1 analoginput]
        SensorRange = [-1 1]
        Type = Channel
        Units = Volts
        UnitsRange = [-1 1]

As described in the preceding section, you can also return values for a specified number of channel properties with the get function or the dot notation.

Configuring and Returning Properties

Configuring Property Values