Get Waveform Subset VI

LabVIEW 2018 Help


Edition Date: March 2018
Part Number: 371361R-01
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Owning Palette: Waveform VIs and Functions

Requires: Base Development System

Retrieves a subset of a waveform at a specified time or index. You must manually select the polymorphic instance you want to use.

Details  Example

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

WDT Get Waveform Subset DBL

open interval? defines whether the waveform subset extracted is an open or closed interval. The default is TRUE, which selects an open interval. For example, if t0 = 0, dt = 1, Y = {0, 1, 2}, start/duration format is Relative Time, start samples/time is 0, and duration is 2, an open interval returns {0, 1}. A closed interval returns {0, 1, 2}.
start/duration format specifies if you want to retrieve the data value of the specified element or at a specified time.

0Samples (default)—Returns the data value of the specified element in the waveform data.
1Relative Time—Returns the data value at a specified time relative to the first point in the waveform. In this mode, the dt of the waveform affects actual start samples/time and actual duration.
waveform in is the waveform for which you want to retrieve a subset.
start samples/time is the data element or time value where you want to start acquiring a waveform subset.
duration is the amount of time to retrieve data or the number of elements of data you want to retrieve, depending on the start/duration format you select.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
waveform out is the waveform subset.
actual start samples/time is the actual data element when the subset was acquired.
actual duration is the actual number of elements retrieved or the actual amount of time the data values were acquired.
error out contains error information. This output provides standard error out functionality.

WDT Get Waveform Subset CDB

open interval? defines whether the waveform subset extracted is an open or closed interval. The default is TRUE, which selects an open interval. For example, if t0 = 0, dt = 1, Y = {0, 1, 2}, start/duration format is Relative Time, start samples/time is 0, and duration is 2, an open interval returns {0, 1}. A closed interval returns {0, 1, 2}.
start/duration format specifies if you want to retrieve the data value of the specified element or at a specified time.

0Samples (default)—Returns the data value of the specified element in the waveform data.
1Relative Time—Returns the data value at a specified time relative to the first point in the waveform. In this mode, the dt of the waveform affects actual start samples/time and actual duration.
waveform in is the waveform for which you want to retrieve a subset.
start samples/time is the data element or time value where you want to start acquiring a waveform subset.
duration is the amount of time to retrieve data or the number of elements of data you want to retrieve, depending on the start/duration format you select.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
waveform out is the waveform subset.
actual start samples/time is the actual data element when the subset was acquired.
actual duration is the actual number of elements retrieved or the actual amount of time the data values were acquired.
error out contains error information. This output provides standard error out functionality.

WDT Get Waveform Subset EXT

open interval? defines whether the waveform subset extracted is an open or closed interval. The default is TRUE, which selects an open interval. For example, if t0 = 0, dt = 1, Y = {0, 1, 2}, start/duration format is Relative Time, start samples/time is 0, and duration is 2, an open interval returns {0, 1}. A closed interval returns {0, 1, 2}.
start/duration format specifies if you want to retrieve the data value of the specified element or at a specified time.

0Samples (default)—Returns the data value of the specified element in the waveform data.
1Relative Time—Returns the data value at a specified time relative to the first point in the waveform. In this mode, the dt of the waveform affects actual start samples/time and actual duration.
waveform in is the waveform for which you want to retrieve a subset.
start samples/time is the data element or time value where you want to start acquiring a waveform subset.
duration is the amount of time to retrieve data or the number of elements of data you want to retrieve, depending on the start/duration format you select.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
waveform out is the waveform subset.
actual start samples/time is the actual data element when the subset was acquired.
actual duration is the actual number of elements retrieved or the actual amount of time the data values were acquired.
error out contains error information. This output provides standard error out functionality.

WDT Get Waveform Subset I16

open interval? defines whether the waveform subset extracted is an open or closed interval. The default is TRUE, which selects an open interval. For example, if t0 = 0, dt = 1, Y = {0, 1, 2}, start/duration format is Relative Time, start samples/time is 0, and duration is 2, an open interval returns {0, 1}. A closed interval returns {0, 1, 2}.
start/duration format specifies if you want to retrieve the data value of the specified element or at a specified time.

0Samples (default)—Returns the data value of the specified element in the waveform data.
1Relative Time—Returns the data value at a specified time relative to the first point in the waveform. In this mode, the dt of the waveform affects actual start samples/time and actual duration.
waveform in is the waveform for which you want to retrieve a subset.
start samples/time is the data element or time value where you want to start acquiring a waveform subset.
duration is the amount of time to retrieve data or the number of elements of data you want to retrieve, depending on the start/duration format you select.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
waveform out is the waveform subset.
actual start samples/time is the actual data element when the subset was acquired.
actual duration is the actual number of elements retrieved or the actual amount of time the data values were acquired.
error out contains error information. This output provides standard error out functionality.

WDT Get Waveform Subset I32

open interval? defines whether the waveform subset extracted is an open or closed interval. The default is TRUE, which selects an open interval. For example, if t0 = 0, dt = 1, Y = {0, 1, 2}, start/duration format is Relative Time, start samples/time is 0, and duration is 2, an open interval returns {0, 1}. A closed interval returns {0, 1, 2}.
start/duration format specifies if you want to retrieve the data value of the specified element or at a specified time.

0Samples (default)—Returns the data value of the specified element in the waveform data.
1Relative Time—Returns the data value at a specified time relative to the first point in the waveform. In this mode, the dt of the waveform affects actual start samples/time and actual duration.
waveform in is the waveform for which you want to retrieve a subset.
start samples/time is the data element or time value where you want to start acquiring a waveform subset.
duration is the amount of time to retrieve data or the number of elements of data you want to retrieve, depending on the start/duration format you select.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
waveform out is the waveform subset.
actual start samples/time is the actual data element when the subset was acquired.
actual duration is the actual number of elements retrieved or the actual amount of time the data values were acquired.
error out contains error information. This output provides standard error out functionality.

WDT Get Waveform Subset I8

open interval? defines whether the waveform subset extracted is an open or closed interval. The default is TRUE, which selects an open interval. For example, if t0 = 0, dt = 1, Y = {0, 1, 2}, start/duration format is Relative Time, start samples/time is 0, and duration is 2, an open interval returns {0, 1}. A closed interval returns {0, 1, 2}.
start/duration format specifies if you want to retrieve the data value of the specified element or at a specified time.

0Samples (default)—Returns the data value of the specified element in the waveform data.
1Relative Time—Returns the data value at a specified time relative to the first point in the waveform. In this mode, the dt of the waveform affects actual start samples/time and actual duration.
waveform in is the waveform for which you want to retrieve a subset.
start samples/time is the data element or time value where you want to start acquiring a waveform subset.
duration is the amount of time to retrieve data or the number of elements of data you want to retrieve, depending on the start/duration format you select.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
waveform out is the waveform subset.
actual start samples/time is the actual data element when the subset was acquired.
actual duration is the actual number of elements retrieved or the actual amount of time the data values were acquired.
error out contains error information. This output provides standard error out functionality.

WDT Get Waveform Subset SGL

open interval? defines whether the waveform subset extracted is an open or closed interval. The default is TRUE, which selects an open interval. For example, if t0 = 0, dt = 1, Y = {0, 1, 2}, start/duration format is Relative Time, start samples/time is 0, and duration is 2, an open interval returns {0, 1}. A closed interval returns {0, 1, 2}.
start/duration format specifies if you want to retrieve the data value of the specified element or at a specified time.

0Samples (default)—Returns the data value of the specified element in the waveform data.
1Relative Time—Returns the data value at a specified time relative to the first point in the waveform. In this mode, the dt of the waveform affects actual start samples/time and actual duration.
waveform in is the waveform for which you want to retrieve a subset.
start samples/time is the data element or time value where you want to start acquiring a waveform subset.
duration is the amount of time to retrieve data or the number of elements of data you want to retrieve, depending on the start/duration format you select.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
waveform out is the waveform subset.
actual start samples/time is the actual data element when the subset was acquired.
actual duration is the actual number of elements retrieved or the actual amount of time the data values were acquired.
error out contains error information. This output provides standard error out functionality.

DWDT Get Waveform Subset

open interval? defines whether the waveform subset extracted is an open or closed interval. The default is TRUE, which selects an open interval. For example, if t0 = 0, dt = 1, Y = {0, 1, 2}, start/duration format is Relative Time, start samples/time is 0, and duration is 2, an open interval returns {0, 1}. A closed interval returns {0, 1, 2}.
start/duration format specifies if you want to retrieve the data value of the specified element or at a specified time.

0Samples (default)—Returns the data value of the specified element in the waveform data.
1Relative Time—Returns the data value at a specified time relative to the first point in the waveform. In this mode, the dt of the waveform affects actual start samples/time and actual duration.
waveform in is the digital waveform for which you want to retrieve a subset.
start samples/time is the data element or time value where you want to start acquiring a waveform subset.
duration is the amount of time to retrieve data or the number of elements of data you want to retrieve, depending on the start/duration format you select.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
waveform out is the waveform subset.
actual start samples/time is the actual data element when the subset was acquired.
actual duration is the actual number of elements retrieved or the actual amount of time the data values were acquired.
error out contains error information. This output provides standard error out functionality.

DTbl Digital Subset

digital data is the set of digital data for which you want to retrieve a subset.
start is the data element or time value where you want to start acquiring a data subset.
number of samples specifies the number of samples to include in digital data subset.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
digital data subset is the digital data subset.
error out contains error information. This output provides standard error out functionality.

Get Waveform Subset Details

For example, consider a waveform of 128 scans with a dt of 1.00. If you wire 40.00 to duration and 25.00 to start samples/time, the actual duration and actual start samples/time are the same, 40.00 and 25.00, respectively. However, if the waveform has a dt of 2.00, the actual duration and the actual start samples/time are 40.00 and 24.00, respectively.

Example

Refer to the Waveform - Get Subset VI in the labview\examples\Waveform directory for an example of using the Get Waveform Subset VI.

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