niScope Fetch Measurement (poly)

NI High-Speed Digitizers Help (NI-SCOPE)

Edition Date: January 2017

Part Number: 370592AB-01

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NI-SCOPE (English | Japanese)

Obtains a waveform from the digitizer and returns the specified measurement.

Refer to Using Fetch VIs for more information. Many of the measurements use the low, mid, and high reference levels. You configure the low, mid, and high references by using a property with Chan Based Low Ref Level, Chan Based Mid Ref Level, and chan based high ref level properties to set each channel differently.

related topics

Use the pull-down menu to select an instance of this VI.

Measurement Cluster

Obtains a waveform from the digitizer and returns the specified measurement array for a single channel and record as a cluster along with timing data.

niScope Fetch Array Measurement Cluster

/images/reference/en-XX/help/370592AB-01/cio.gif

instrument handle identifies a particular instrument session.

/images/reference/en-XX/help/370592AB-01/cstr.gif

channels specifies the channel from which to acquire data.

For more information, refer to Channel String Syntax.

/images/reference/en-XX/help/370592AB-01/ci32.gif

array measurement is the array measurement to add as a processing step.

Default Value: None

Refer to the list of NI-SCOPE Array Measurements for more information.

/images/reference/en-XX/help/370592AB-01/cdbl.gif

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.

/images/reference/en-XX/help/370592AB-01/cerrcodeclst.gif

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

/images/reference/en-XX/help/370592AB-01/ci32.gif

meas waveform size is the maximum number of samples returned in the measurement waveform array for each waveform measurement.

Default Value: –1 (returns all available samples)

Note  Use the property Fetch Meas Num Samples to set the number of samples to fetch when performing a measurement. For more information about when to use this property with the niScope Fetch Measurement VI, refer to the NI KnowledgeBase.
/images/reference/en-XX/help/370592AB-01/iio.gif

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

/images/reference/en-XX/help/370592AB-01/inclst.gif

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

/images/reference/en-XX/help/370592AB-01/ii32.gif

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.

/images/reference/en-XX/help/370592AB-01/idbl.gif

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.

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

offset is the offset factor of the given channel.

Use for scaling binary data with the following formula:

voltage = binary data × gain factor + offset

/images/reference/en-XX/help/370592AB-01/idbl.gif

gain is the gain factor of the given channel.

Use for scaling binary data with the following formula:

voltage = binary data × gain factor + offset

/images/reference/en-XX/help/370592AB-01/idbl.gif

reserved1 is reserved. Do not use.

/images/reference/en-XX/help/370592AB-01/idbl.gif

reserved2 is reserved. Do not use.

/images/reference/en-XX/help/370592AB-01/icclst.gif

meas waveform returns a single record for single channel as a cluster for wiring to a graph, including the timing information.

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/i1ddbl.gif

measWfm returns a one-dimensional array of data for one waveform.

/images/reference/en-XX/help/370592AB-01/ierrcodeclst.gif

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

Measurement 1D DBL

Obtains a waveform from the digitizer and returns the specified measurement voltage data for a single channel and record.

niScope Fetch Array Measurement

/images/reference/en-XX/help/370592AB-01/cio.gif

instrument handle identifies a particular instrument session.

/images/reference/en-XX/help/370592AB-01/cstr.gif

channels specifies the channel from which to acquire data.

For more information, refer to Channel String Syntax.

/images/reference/en-XX/help/370592AB-01/ci32.gif

array measurement is the array measurement to add as a processing step.

Default Value: None

Refer to the list of NI-SCOPE Array Measurements for more information.

/images/reference/en-XX/help/370592AB-01/cdbl.gif

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.

/images/reference/en-XX/help/370592AB-01/cerrcodeclst.gif

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

/images/reference/en-XX/help/370592AB-01/ci32.gif

meas waveform size is the maximum number of samples returned in the measurement waveform array for each waveform measurement.

Default Value: –1 (returns all available samples)

Note  Use the property Fetch Meas Num Samples to set the number of samples to fetch when performing a measurement. For more information about when to use this property with the niScope Fetch Measurement VI, refer to the NI KnowledgeBase.
/images/reference/en-XX/help/370592AB-01/iio.gif

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

/images/reference/en-XX/help/370592AB-01/inclst.gif

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

/images/reference/en-XX/help/370592AB-01/ii32.gif

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.

/images/reference/en-XX/help/370592AB-01/idbl.gif

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.

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

offset is the offset factor of the given channel.

Use for scaling binary data with the following formula:

voltage = binary data × gain factor + offset

/images/reference/en-XX/help/370592AB-01/idbl.gif

gain is the gain factor of the given channel.

Use for scaling binary data with the following formula:

voltage = binary data × gain factor + offset

/images/reference/en-XX/help/370592AB-01/idbl.gif

reserved1 is reserved. Do not use.

/images/reference/en-XX/help/370592AB-01/idbl.gif

reserved2 is reserved. Do not use.

/images/reference/en-XX/help/370592AB-01/i1ddbl.gif

measWfm returns a one-dimensional array of data for one waveform.

/images/reference/en-XX/help/370592AB-01/ierrcodeclst.gif

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

Measurement 1D Cluster

Obtains a waveform from the digitizer and returns the specified array measurement for multiple channels and records as a cluster.

niScope Multi Fetch Array Measurement Cluster

/images/reference/en-XX/help/370592AB-01/cio.gif

instrument handle identifies a particular instrument session.

/images/reference/en-XX/help/370592AB-01/cstr.gif

channels specifies the channel from which to acquire data.

For more information, refer to Channel String Syntax.

/images/reference/en-XX/help/370592AB-01/ci32.gif

array measurement is the array measurement to add as a processing step.

Default Value: None

Refer to the list of NI-SCOPE Array Measurements for more information.

/images/reference/en-XX/help/370592AB-01/cdbl.gif

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.

/images/reference/en-XX/help/370592AB-01/cerrcodeclst.gif

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

/images/reference/en-XX/help/370592AB-01/ci32.gif

meas waveform size is the maximum number of samples returned in the measurement waveform array for each waveform measurement.

Default Value: –1 (returns all available samples)

Note  Use the property Fetch Meas Num Samples to set the number of samples to fetch when performing a measurement. For more information about when to use this property with the niScope Fetch Measurement VI, refer to the NI KnowledgeBase.
/images/reference/en-XX/help/370592AB-01/iio.gif

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

/images/reference/en-XX/help/370592AB-01/i1dnclst.gif

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

/images/reference/en-XX/help/370592AB-01/ii32.gif

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.

/images/reference/en-XX/help/370592AB-01/idbl.gif

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.

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

offset is the offset factor of the given channel.

Use for scaling binary data with the following formula:

voltage = binary data × gain factor + offset

/images/reference/en-XX/help/370592AB-01/idbl.gif

gain is the gain factor of the given channel.

Use for scaling binary data with the following formula:

voltage = binary data × gain factor + offset

/images/reference/en-XX/help/370592AB-01/idbl.gif

reserved1 is reserved. Do not use.

/images/reference/en-XX/help/370592AB-01/idbl.gif

reserved2 is reserved. Do not use.

/images/reference/en-XX/help/370592AB-01/i1dcclst.gif

meas waveform returns an array of clusters for wiring to a graph, including the timing information.

If you specify a channel list, NI-SCOPE returns the waveforms in the list order. NI-SCOPE returns these records sequentially, so all record 0 waveforms are first. For example, with a two-channel list, you would have the following index values:

index 0 = record 0, channel 0

index 1 = record 0, channel 1

index 2 = record 1, channel 0

index 3 = record 1, channel 1

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/i1ddbl.gif

measWfm returns a one-dimensional array of data for one waveform.

/images/reference/en-XX/help/370592AB-01/ierrcodeclst.gif

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

Measurement 2D DBL

Obtains a waveform from the digitizer and returns the specified measurement voltage data. Unlike the Measurement 1D DBL instance of the niScope Fetch Measurement VI, the Measurement 2D DBL instance can fetch data from multiple channels and records.

niScope Multi Fetch Array Measurement

/images/reference/en-XX/help/370592AB-01/cio.gif

instrument handle identifies a particular instrument session.

/images/reference/en-XX/help/370592AB-01/cstr.gif

channels specifies the channel from which to acquire data.

For more information, refer to Channel String Syntax.

/images/reference/en-XX/help/370592AB-01/ci32.gif

array measurement is the array measurement to add as a processing step.

Default Value: None

Refer to the list of NI-SCOPE Array Measurements for more information.

/images/reference/en-XX/help/370592AB-01/cdbl.gif

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.

/images/reference/en-XX/help/370592AB-01/cerrcodeclst.gif

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

/images/reference/en-XX/help/370592AB-01/ci32.gif

meas waveform size is the maximum number of samples returned in the measurement waveform array for each waveform measurement.

Default Value: –1 (returns all available samples)

Note  Use the property Fetch Meas Num Samples to set the number of samples to fetch when performing a measurement. For more information about when to use this property with the niScope Fetch Measurement VI, refer to the NI KnowledgeBase.
/images/reference/en-XX/help/370592AB-01/iio.gif

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

/images/reference/en-XX/help/370592AB-01/i1dnclst.gif

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

/images/reference/en-XX/help/370592AB-01/ii32.gif

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.

/images/reference/en-XX/help/370592AB-01/idbl.gif

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.

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

offset is the offset factor of the given channel.

Use for scaling binary data with the following formula:

voltage = binary data × gain factor + offset

/images/reference/en-XX/help/370592AB-01/idbl.gif

gain is the gain factor of the given channel.

Use for scaling binary data with the following formula:

voltage = binary data × gain factor + offset

/images/reference/en-XX/help/370592AB-01/idbl.gif

reserved1 is reserved. Do not use.

/images/reference/en-XX/help/370592AB-01/idbl.gif

reserved2 is reserved. Do not use.

/images/reference/en-XX/help/370592AB-01/i2ddbl.gif

wfm is an array of waveforms; that is, a two-dimensional array. This output can be wired directly to the LabVIEW waveform graph, but each waveform is plotted without timing information.

The 2D array 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" and the record number set to –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.

/images/reference/en-XX/help/370592AB-01/ierrcodeclst.gif

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

Statistics Cluster

Obtains a waveform measurement and returns the measurement value for a single channel and record. Specify a particular measurement type, such as rise time, frequency, or voltage peak-to-peak. The waveform on which the digitizer calculates the waveform measurement is from an acquisition that you previously initiated. The statistics for the specified measurement are also returned, where the statistics are updated once every acquisition when the specified measurement is fetched by any of the Fetch/Read measurement VIs.

niScope Fetch Measurement Stats

/images/reference/en-XX/help/370592AB-01/cio.gif

instrument handle identifies a particular instrument session.

/images/reference/en-XX/help/370592AB-01/cstr.gif

channels specifies the channel from which to acquire data.

For more information, refer to Channel String Syntax.

/images/reference/en-XX/help/370592AB-01/ci32.gif

scalar measurement is the measurement to perform on the waveform read from the digitizer.

Refer to the list of NI-SCOPE Scalar Measurements for more information.

/images/reference/en-XX/help/370592AB-01/cdbl.gif

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.

/images/reference/en-XX/help/370592AB-01/cerrcodeclst.gif

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

/images/reference/en-XX/help/370592AB-01/iio.gif

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

/images/reference/en-XX/help/370592AB-01/inclst.gif

stats contains the resulting measurement data.

/images/reference/en-XX/help/370592AB-01/idbl.gif

result contains the measurement acquired.

/images/reference/en-XX/help/370592AB-01/idbl.gif

mean returns the mean scalar value, which is obtained by averaging each niScope Fetch Measurement Stats call.

/images/reference/en-XX/help/370592AB-01/idbl.gif

stdev returns the standard deviation.

/images/reference/en-XX/help/370592AB-01/idbl.gif

min returns the smallest scalar value acquired.

/images/reference/en-XX/help/370592AB-01/idbl.gif

max returns the largest scalar value acquired.

/images/reference/en-XX/help/370592AB-01/ii32.gif

num in stats returns the number of measurements used to calculate the statistics.

/images/reference/en-XX/help/370592AB-01/ierrcodeclst.gif

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

Statistics 1D Cluster

Obtains a waveform measurement and returns the measurement value for multiple channel and multiple record acquisitions.

Specify a particular measurement type, such as rise time, frequency, or voltage peak-to-peak. The waveform on which the digitizer calculates the waveform measurement is from an acquisition that you previously initiated. The statistics for the specified measurement are also returned, where the statistics are updated once every acquisition when the specified measurement is fetched by any of the Fetch/Read waveform measurement VIs.

niScope Multi Fetch Measurement Stats

/images/reference/en-XX/help/370592AB-01/cio.gif

instrument handle identifies a particular instrument session.

/images/reference/en-XX/help/370592AB-01/cstr.gif

channels specifies the channel from which to acquire data.

For more information, refer to Channel String Syntax.

/images/reference/en-XX/help/370592AB-01/ci32.gif

scalar measurement is the measurement to perform on the waveform read from the digitizer.

Refer to the list of NI-SCOPE Scalar Measurements for more information.

/images/reference/en-XX/help/370592AB-01/cdbl.gif

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.

/images/reference/en-XX/help/370592AB-01/cerrcodeclst.gif

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

/images/reference/en-XX/help/370592AB-01/iio.gif

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

/images/reference/en-XX/help/370592AB-01/i1dnclst.gif

stats is an array of clusters with scalar measurement results and statistics.

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 multi fetch measurement VI during a normal acquisition with the channel list "0,1", the order of the results output is:

statistics for record 0, channel 0,

statistics for record 0, channel 1,

statistics for record 1, channel 0,

statistics for record 1, channel 1

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

scalar result contains the measurement.

/images/reference/en-XX/help/370592AB-01/idbl.gif

mean returns the mean scalar value, which is obtained by averaging each niScope Multi Fetch Measurement Stats call.

/images/reference/en-XX/help/370592AB-01/idbl.gif

stdev returns the standard deviation.

/images/reference/en-XX/help/370592AB-01/idbl.gif

min returns the smallest scalar value acquired.

/images/reference/en-XX/help/370592AB-01/idbl.gif

max returns the largest scalar value acquired.

/images/reference/en-XX/help/370592AB-01/ii32.gif

num in stats returns the number of measurements used to calculate the statistics.

/images/reference/en-XX/help/370592AB-01/ierrcodeclst.gif

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

Measurement Scalar DBL

Obtains a waveform from the digitizer and returns the specified measurement voltage data for a single channel and record.

niScope Fetch Measurement

/images/reference/en-XX/help/370592AB-01/cio.gif

instrument handle identifies a particular instrument session.

/images/reference/en-XX/help/370592AB-01/cstr.gif

channels specifies the channel from which to acquire data.

For more information, refer to Channel String Syntax.

/images/reference/en-XX/help/370592AB-01/ci32.gif

scalar measurement is the measurement to perform on the waveform read from the digitizer.

Refer to the list of NI-SCOPE Scalar Measurements for more information.

/images/reference/en-XX/help/370592AB-01/cdbl.gif

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.

/images/reference/en-XX/help/370592AB-01/cerrcodeclst.gif

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

/images/reference/en-XX/help/370592AB-01/iio.gif

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

/images/reference/en-XX/help/370592AB-01/idbl.gif

result contains the measurement acquired.

/images/reference/en-XX/help/370592AB-01/ierrcodeclst.gif

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

Measurement Scalar 1D DBL

Fetches a waveform from the digitizer and performs the specified waveform measurement. Use this function for multiple channel and multiple record acquisitions.

niScope Multi Fetch Measurement

/images/reference/en-XX/help/370592AB-01/cio.gif

instrument handle identifies a particular instrument session.

/images/reference/en-XX/help/370592AB-01/cstr.gif

channels specifies the channel from which to acquire data.

For more information, refer to Channel String Syntax.

/images/reference/en-XX/help/370592AB-01/ci32.gif

scalar measurement is the measurement to perform on the waveform read from the digitizer.

Refer to the list of NI-SCOPE Scalar Measurements for more information.

/images/reference/en-XX/help/370592AB-01/cdbl.gif

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.

/images/reference/en-XX/help/370592AB-01/cerrcodeclst.gif

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

/images/reference/en-XX/help/370592AB-01/iio.gif

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

/images/reference/en-XX/help/370592AB-01/i1ddbl.gif

results contains the measurements acquired as a one-dimensional array; if you specify a channel list, NI-SCOPE returns the waveforms in the list order. NI-SCOPE returns these records sequentially, so all record 0 waveforms are first.

For example, with a two-channel list, you would have the following index values:

index 0 = record 0, channel 0

index 1 = record 0, channel 1

index 2 = record 1, channel 0

index 3 = record 1, channel 1

/images/reference/en-XX/help/370592AB-01/ierrcodeclst.gif

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

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