niHWS_RetrieveAnalogWfmF64

NI-HWS C Function Reference

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niHWS_RetrieveAnalogWfmF64

C Function Prototype

tHWS_Status niHWS_RetrieveAnalogWfmF64 (const char filePath[], double* rate, double* gain, double* offset, long wfmBufferSize, double* wfmBuffer, long* numSamplesInWfm);

Purpose

Retrieves the analog waveform as double-precision floating-point data from the file specified.

Parameters

Name Type Description
filePath const char[] Specifies the path and filename of the HWS file to create or open. The .hws extension is typically used for HWS files, although using this extension is optional.
rate double* The rate of the Sample clock used to capture the waveform.
gain double* This parameter is equivalent to element 1 of the coeffArray.

NI-HWS stores polynomial scaling coefficients that are intended to be applied to waveform data by your application or your hardware. The offset and gain parameters in the high-level Store and Retrieve functions are identical to the first two elements of the coeffArray in the Get and Set Scaling Coefficients functions.

Note  If a waveform stored as integers is retrieved by this function, NI-HWS scales the integers to floating point numbers using the coeffArray and sets the gain parameter to 1.
offset double* This parameter is equivalent to element 0 of the coeffArray.

NI-HWS stores polynomial scaling coefficients that are intended to be applied to waveform data by your application or your hardware. The offset and gain parameters in the high-level Store and Retrieve functions are identical to the first two elements of the coeffArray in the Get and Set Scaling Coefficients functions.

Note  If a waveform stored as integers is retrieved by this function, NI-HWS scales the integers to floating point numbers using the coeffArray and sets the offset parameter to 0.
wfmBufferSize long Specifies how many samples to read into wfmBuffer.

If wfmBufferSize is 0, the total number of samples in the waveform is returned in numSamplesInWfm.
wfmBuffer double* Contains the data for the waveform. This array must be large enough to contain at least the amount of data indicated by the value assigned to wfmBufferSize.
numSamplesInWfm long* Returns the total number of samples in the waveform.

Return Value

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