IviDigitizer Fetch Multi Record Waveform Int8 [MRA]
IviDigitizerMultiRecordAcquisition Capability Group
Returns the (multi-record) waveform the digitizer acquired for the specified channel. The waveform is from a previously initiated acquisition.
Refer to the notes following the input and output descriptions for more information about using this VI.
![IviDigitizer Fetch Multi Record Waveform Int8 [MRA].vi](ividigitizer_fetch_multi_record_waveform_int8_[mra]c.gif)
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Waveform Array Size (256) Specifies the allocated size of the WaveformArray buffer, in number of data points.
If this value is smaller than the total number of points to be retrieved, the driver will fill the waveform buffer as fully as possible and return the actual number of points retrieved in the Actual Points output. Default Value: 256 |
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instrument handle Returns an instrument handle that you use to identify the instrument in all subsequent instrument driver VI calls.
Notes: (1) This VI creates a new session each time you invoke it. This is useful if you have multiple physical instances of the same type of instrument. (2) Avoid creating multiple concurrent sessions to the same physical instrument. Although you can create more than one IVI session for the same resource, it is best not to do so. A better approach is to use the same IVI session in multiple execution threads. |
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Channel Name ("") Specifies the name of the channel from which to retrieve the data.
Default Value: "" Note: You can specify the trace name as a string variable or as a literal enclosed in double quotes. |
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First Record (1) Specifies the number of the first record to read.
Default Value: 1 |
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Num of Records (256) Specifies the number of consecutive records to read.
If Num of Records is greater than 1, this input allows full or partial (if Offset Within Record and Num of Points Per Record are specified accordingly) data to be retrieved from multiple digitizer records in a single Fetch call. If Num of Records is less than or equal to zero, an error will be returned. Default Value: 256 |
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Offset Within Record (0) Specifies the start index within the record from which the data should be retrieved.
While normally zero, this parameter allows users to retrieve partial records using non-zero values. Data that comes before the Offset Within Record index will not be retrieved. This is perhaps most useful when retrieving very large data records because it allows records to be retrieved in several smaller chunks. Default Value: 0 |
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error in (no error) The error in cluster can accept error information wired from VIs previously called. Use this information to decide if any functionality should be bypassed in the event of errors from other VIs.
The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed. |
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Num of Points Per Record (256) Specifies the number of data points to return.
This number may be larger than the amount of data available. Use the Actual Points output to determine how many data points were returned. Default Value: 256 |
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Initial X Offset The time in relation to the Trigger Event of the first point in the waveform in seconds. Negative values mean that the first point in the waveform array was acquired before the trigger event. |
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Initial X Time Seconds Specifies the seconds portion of the absolute time at which the first data point was acquired.
Notes: The actual time is the sum of Initial X Time Seconds and Initial X Time Fraction. The time is specified as the sum of two values because a single double-precision floating-point number does not have sufficient range and resolution to specify the time. |
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Initial X Time Fraction Specifies the fractional portion of the absolute time at which the first data point was acquired.
Notes: The actual time is the sum of Initial X Time Seconds and Initial X Time Fraction. The time is specified as the sum of two values because a single double-precision floating-point number does not have sufficient range and resolution to specify the time. |
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instrument handle out Returns an instrument handle that you use to identify the instrument in all subsequent instrument driver VI calls.
Notes: (1) This VI creates a new session each time you invoke it. This is useful if you have multiple physical instances of the same type of instrument. (2) Avoid creating multiple concurrent sessions to the same physical instrument. Although you can create more than one IVI session for the same resource, it is best not to do so. A better approach is to use the same IVI session in multiple execution threads. |
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Waveform Array Buffer into which the acquired waveform is stored.
Note: This array is always user allocated, and it must contain at least as many elements as the value you specify in the Waveform Array Size input. |
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Actual Records Indicates how many records in the acquisition completed successfully. |
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Actual Points Indicates how many data points were actually retrieved from the instrument for each completed record. This is an array of size at least Num of Records or a NULL pointer. For IVI-C, this array is always user allocated. |
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First Valid Point Indicates the index of the first valid data point in the output Data array for each completed record. This value will often be zero. However, some digitizer hardware designs transfer data most efficiently when the data is aligned with specific memory address boundaries. In those cases, the hardware may return a few invalid data points at the beginning of a record. This eliminates the need to shift the data during the transfer, ensuring maximum data transfer rates. This is an array of size at least Num of Records or a NULL pointer. For IVI-C, this array is always user allocated. |
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error out The error out cluster passes error or warning information out of a VI to be used by other VIs.
The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed. |
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X Increment The time between points in the acquired waveform in seconds. |
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Scale Factor Scaling factor for the waveform data. |
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Scale Offset Scaling offset for the waveform data. |
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Notes
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