National Instruments Welding System 321645c-01 사용자 설명서
Chapter 2
Function Reference — SCAN_Op
NI-DAQ FRM for PC Compatibles
2-298
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National Instruments Corporation
Voltage Calculation
, for valid gain settings. If you use an invalid gain, NI-DAQ returns an
error.
count is the number of samples to be acquired (that is, the number of A/D conversions to be
performed).
performed).
Range:
3 through 2
32
– 1 (except the E Series).
2 through 2
24
* (total number of channels scanned) or 2
32
– 1, whichever is less
(E Series and DSA devices). 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 NI-DAQ
samples channels within a scan sequence.
samples channels within a scan sequence.
Range:
Roughly 0.00153 pts/s through 500,000 pts/s. The maximum rate varies
according to the type of device you have.
according to the type of device you have.
scanRate is the scan rate you want in units of scans per second (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.
which NI-DAQ 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 up to 5,000,000 scans/s. A value of 0 means that
there is no delay between scans and that the effective scanRate is
sampleRate/numChans.
there is no delay between scans and that the effective scanRate is
sampleRate/numChans.
When scanRate is not 0, scanRate must allow a minimum delay between the last channel of
the scan and the first channel of the next scan.scan. This delay must be at least 11 µs on the
AT-MIO-16X and 6 µs on the AT-MIO-16F-5 and AT-MIO-64F-5. For E Series devices, this
delay corresponds exactly to the speed of the board: for example, 1 µs for an E-1 board, 2 µs
for an E-2 board, and so on.
the scan and the first channel of the next scan.scan. This delay must be at least 11 µs on the
AT-MIO-16X and 6 µs on the AT-MIO-16F-5 and AT-MIO-64F-5. For E Series devices, this
delay corresponds exactly to the speed of the board: for example, 1 µs for an E-1 board, 2 µs
for an E-2 board, and so on.
Note
Simultaneous sampling devices do not use the sampleRate parameter. Because
these devices use simultaneous sampling of all channels the scanRate parameter
controls the acquisition rate; therefore, scanRate of 0 is not allowed.
these devices use simultaneous sampling of all channels the scanRate parameter
controls the acquisition rate; therefore, scanRate of 0 is not allowed.
buffer is an integer array that must have a length not less than count. When
SCAN_Op
returns
with an error code equal to zero, buffer contains the acquired data.
4 represents a four-to-one multiplexer.
Using This Function
SCAN_Op
initiates a synchronous process of acquiring A/D conversion samples and storing
them in a buffer.
SCAN_Op
does not return control to your application until NI-DAQ acquires
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 buffer
and ignores any subsequent conversions.
mode (with pretrigger mode disabled), the process stores count A/D conversions in the buffer
and ignores any subsequent conversions.