Retrieves the waveform the digitizer has acquired for multiple channels and records. Returns a one-dimensional array of complex, scaled waveforms in clusters that include timing information.


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Inputs/Outputs

  • cdbl.png timeout —

    timeout is the time (in seconds) to wait for the data to be acquired. Use 0 for this parameter to tell NI-SCOPE to fetch whatever is currently available. Using -1 for this parameter implies infinite timeout.

  • civrn.png instrument handle —

    instrument handle identifies a particular instrument session.

  • cstr.png channels —

    channels specifies the channel(s) from which to acquire data. For more information, refer to Channel String Syntax.

  • ci32.png numSamples —

    numSamples is the maximum number of samples to fetch for each waveform; if the acquisition finishes with fewer points than requested, some devices return partial data if the acquisition finished, was aborted, or a timeout of 0 was used. Use –1 for this parameter if you want to fetch all available samples. The VI reads the actual record length and attempts to acquire all available samples. If it fails to complete within the timeout period, the VI returns an error.

  • cerrcodeclst.png error in —

    error in describes error conditions that occur before this node runs. This input provides standard error in functionality.

  • iivrn.png instrument handle out —

    instrument handle out has the same value as the instrument handle.

  • i1dnclst.png wfm info —

    wfm info contains all the timing and scaling information about the waveform.

  • ii32.png actualSamples —

    actualSamples is the actual number of samples in the acquired waveform; this number may be less than numSamples if the number you request is not available.

  • idbl.png absoluteInitialX —

    absoluteInitialX is the timestamp in seconds of the first fetched sample. This timestamp is comparable between records and acquisitions; devices that do not support this parameter use 0 for this output.

  • idbl.png relativeInitialX —

    relativeInitialX is the time in seconds from the trigger to the first sample in the acquired waveform.

  • idbl.png xIncrement —

    xIncrement indicates the time in seconds between two samples in the acquired waveform.

  • idbl.png offset —

    offset is the offset factor of the given channel.

    Use for scaling binary data with the following formula:

    voltage = binary data × gain factor + offset

  • idbl.png gain —

    gain is the gain factor of the given channel.

    Use for scaling binary data with the following formula:

    voltage = binary data × gain factor + offset

  • idbl.png reserved1 —

    reserved1 is reserved. Do not use.

  • idbl.png reserved2 —

    reserved2 is reserved. Do not use.

  • i1dcclst.png waveform —

    waveform is an array of clusters, each containing the initial time value, time increment, and a waveform array. The initial time value in the cluster is the value relative to the trigger. The relative initial time value is the time from the trigger to the first point so the trigger always occurs at time equals zero.

    The array of clusters includes waveforms from multiple channels, records, and acquisition types. For example, if the acquisition type is normal there is one waveform per channel per record. If you call the fetch VI during a normal acquisition with the channel string "0,1" the order of the output is:

    record 0, channel 0,

    record 0, channel 1,

    record 1, channel 0,

    record 1, channel 1,

    The order of the channels is the order specified by the channels parameter.

  • idbl.png t0 —

    t0 is the initial time value relative to the trigger, such that the trigger always occurs at time equals zero.

  • idbl.png dt —

    dt is the time interval between two samples in the waveform. This value is 1/(sampling rate) for time-domain acquisitions.

  • i1dcdb.png Y —

    Y is an array of waveform data containing one waveform.

  • ierrcodeclst.png error out —

    error out contains error information. This output provides standard error out functionality.