niScope_FetchBinary16

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Updated2023-02-21
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C Function Prototype

ViStatus niScope_FetchBinary16 (ViSession vi, ViConstString channelList, ViReal64 timeout, ViInt32 numSamples, ViInt16* wfm, struct niScope_wfmInfo* wfmInfo);

Purpose

Retrieves data from a previously initiated acquisition and returns binary 16-bit waveforms. This function may return multiple waveforms depending on the number of channels, the acquisition type, and the number of records you specify.

Refer to Using Fetch Functions for more information on using this function.

Note Some functionality, such as time stamping, is not supported in all digitizers. Refer to Features Supported by Device for more information.

Parameters

Input
Name	Type	Description
vi	ViSession	The instrument handle you obtain from niScope_init that identifies a particular instrument session.
channelList	ViConstString	The channel to configure. For more information, refer to Channel String Syntax.
timeout	ViReal64	The time to wait in seconds for data to be acquired; using 0 for this parameter tells NI-SCOPE to fetch whatever is currently available. Using -1 for this parameter implies infinite timeout.
numSamples	ViInt32	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. If it fails to complete within the timeout period, the function returns an error.
Output
Name	Type	Description
wfm	ViInt16*	Returns an array whose length is the numSamples times number of waveforms. Call niScope_ActualNumWfms to determine the number of waveforms. NI-SCOPE returns this data sequentially, so all record 0 waveforms are first. For example, with a channel list of 0,1, you would have the following index values: index 0 = record 0, channel 0 index x = record 0, channel 1 index 2x = record 1, channel 0 index 3x = record 1, channel 1 Where x = the record length
wfmInfo	struct niScope_ wfmInfo*	Returns an array of structures with the following timing and scaling information about each waveform: relativeInitialX—the time (in seconds) from the trigger to the first sample in the fetched waveform absoluteInitialX—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. xIncrement—the time between points in the acquired waveform in seconds actualSamples—the actual number of samples fetched and placed in the waveform array gain—the gain factor of the given channel; useful for scaling binary data with the following formula: voltage = binary data × gain factor + offset offset—the offset factor of the given channel; useful for scaling binary data with the following formula: voltage = binary data × gain factor + offset Call niScope_ActualNumWfms to determine the size of this array.

Return Value

Name Type Description

Status

ViStatus

Reports the status of this operation. To obtain a text description of the status code, call niScope_GetErrorMessage. To obtain additional information concerning the error condition, use niScope_GetError and niScope_ClearError. The general meaning of the status code is as follows:

Value	Meaning
0	Success
Positive Values	Warnings
Negative Values	Errors

NI-SCOPE C Function Reference

Table of Contents

niScope_FetchBinary16

C Function Prototype

Purpose

Parameters

Return Value