Measurement Computing UL for NI LabVIEW - Manual (Page 86)

Universal Library Virtual Instruments (VIs) Streamer File VIs
FilePret.VI
Scan a range of channels continuously while waiting for a trigger. After the trigger occurs, return the specified
number of samples including the specified number of pre-trigger samples to a disk file. This VI waits for a
trigger signal to occur on the Trigger Input. After the trigger occurs, it returns the specified number
(TotalCount) of A/D samples including the specified number of pre-trigger points. It collects the data at the
specified sampling rate (Rate) from the specified range (LowChan-HighChan) of A/D channels from the
specified board. If the A/D board has programmable gain then it sets the gain to the specified range. The
collected data is returned to a file. Refer to the board-specific information contained in the Universal Library
User's Guide (available on our web site at
www.mccdaq.com/PDFmanuals/sm-ul-user-guide.pdf ) to determine
if this function is supported by your board.
Summary:
Inputs: BoardNum [U32] - The board number assigned when installed with InstaCal. Can
be 0 to 100.
LowChan [I32] - First A/D channel of scan.
HighChan [I32] - Last A/D channel of scan.
PretrigCount [I32] - Number of pre-trigger samples to collect.
TotalCount [I32] - Total number of samples to collect.
Rate [I32] - Sample rate in samples per second (Hz) per channel.
Range [I32] - A/D range.
FileName [abc] - Name of disk file.
ExtClock [TF] - External (True) or internal clock (False - default).
DTConnect [TF] - DT connect option (True).
Outputs: PretrigCount [I32] - Number of pre-trigger sample collected.
TotalCount [I32] - Total number of samples collected.
Rate [I32] - Actual sampling rate.
ErrCode [I32] - Error code. See ErrMsg.VI.
Arguments:
BoardNum The board number associated with a board when it was installed with InstaCal. The
specified board must have an A/D and pretrigger capability.
LowChan First A/D channel of scan.
HighChan Last A/D channel of scan.
Low/High Channel #: The maximum allowable channel depends on which type of
A/D board is being used. For boards that have both single-ended and differential
inputs, the maximum allowable channel number also depends on how the board is
configured. For example, a PCI-DAS6025 has 8 channels for differential, 16 for
single-ended mode.
PretrigCount Specifies the number of samples before the trigger that will be returned.
PreTrigCount must be less than TotalCount - 512.
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