National Instruments Welding System 321645c-01 사용자 설명서
Chapter 2
Function Reference — SCAN_to_Disk
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National Instruments Corporation
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NI-DAQ FRM for PC Compatibles
count is the number of samples to be acquired (that is, the number of A/D conversions to be
performed). The length of your data file should be exactly twice the value of count. If you
have previously enabled pretrigger mode (by a call to
performed). The length of your data file should be exactly twice the value of count. If you
have previously enabled pretrigger mode (by a call to
DAQ_StopTrigger_Config
),
NI-DAQ ignores the count parameter.
Range:
3 through 2
32
– 1 (except the E Series).
2 through 2
24
(E Series). For PCI-611X devices, count must be EVEN.
sampleRate is the sample rate you want in units of pts/s. This is the rate at which channels
are sampled within a scan sequence.
are sampled within a scan sequence.
Range:
Roughly 0.00153 pts/s through 500,000 pts/s.
scanRate is the scan rate you want in units of scans/s. This is the rate at which NI-DAQ
performs scans. NI-DAQ performs a scan each time the function samples all the channels
listed in the scan sequence.
performs scans. NI-DAQ performs a scan each time the function samples all the channels
listed in the scan sequence.
Range:
0 and roughly 0.00153 scans/s through 500,000 scans/s. A value of zero means
that there is no delay between scans and that the effective scanRate is
sampleRate/numChans.
that there is no delay between scans and that the effective scanRate is
sampleRate/numChans.
concat enables concatenation of data to an existing file. Regardless of the value of concat,
if the file does not exist, NI-DAQ creates the file.
if the file does not exist, NI-DAQ creates the file.
0:
Overwrite file if it exists.
1:
Concatenate new data to an existing file.
Using This Function
SCAN_to_Disk
initiates a synchronous process of acquiring A/D conversion samples
and storing them in a disk file. The maximum rate varies according to the type of device you
have and the speed and degree of fragmentation of your disk storage device.
have and the speed and degree of fragmentation of your disk storage device.
SCAN_to_Disk
does not return control to your application until NI-DAQ acquires and saves all the samples
you want (or until an acquisition error occurs). When you use posttrigger mode (with
pretrigger mode disabled), the process stores count A/D conversions in the file and ignores
any subsequent conversions.
you want (or until an acquisition error occurs). When you use posttrigger mode (with
pretrigger mode disabled), the process stores count A/D conversions in the file and ignores
any subsequent conversions.
Note
If you have selected external start triggering of the data acquisition operation,
a high-to-low edge at the STARTTRIG* I/O connector of the MIO-16 and
AT-MIO-16D, or the EXTTRIG* connector of the AT-MIO-16F-5,
AT-MIO-64F-5, and AT-MIO-16X initiates the data acquisition operation. If you
are using all E Series devices, see the
a high-to-low edge at the STARTTRIG* I/O connector of the MIO-16 and
AT-MIO-16D, or the EXTTRIG* connector of the AT-MIO-16F-5,
AT-MIO-64F-5, and AT-MIO-16X initiates the data acquisition operation. If you
are using all E Series devices, see the
Select_Signal
function for information
about the external timing signals. Be aware that if you do not apply the start
trigger,
trigger,
SCAN_to_Disk
does not return control to your application. Otherwise,
SCAN_to_Disk
issues a software trigger to initiate the data acquisition operation.
If you have enabled pretrigger mode, the sample counter does not begin counting acquisitions
until you apply a signal at the stop trigger input. Until you apply this signal, the acquisition
continues to write data into the disk file. NI-DAQ ignores the value of the count parameter
until you apply a signal at the stop trigger input. Until you apply this signal, the acquisition
continues to write data into the disk file. NI-DAQ ignores the value of the count parameter