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Chapter 2 Function Reference — Lab_ISCAN_Op
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National Instruments Corporation 2-267 NI-DAQ FRM for PC Compatibles
Range: 1 through 4 for the 516 and Lab and 1200 Series devices in differential mode.
1 through 8 for DAQCard-500 (single-ended mode only).
1 through 8 for DAQCard-700 in differential mode.
1 through 8 for the Lab and 1200 Series devices in single-ended mode.
1 through 16 for LPM devices or DAQCard-700 in single-ended mode.
gain is the gain setting to be used for the scanning operation. The same gain is applied to all
the channels scanned. This gain setting applies only to the DAQ device; if you use SCXI
modules with additional gain selection, you must establish any gain you want at the SCXI
module either by setting jumpers on the module or by calling
SCXI_Set_Gain. The
following gain settings are valid for the Lab and 1200 Series devices—1, 2, 5, 10, 20, 50, and
100. If you use an invalid gain, NI-DAQ returns an error. NI-DAQ ignores gain for the
DAQCard-500/700 and 516 and LPM devices.
buffer is an integer array. buffer must have a length not less than count. When
Lab_ISCAN_Op returns with an error code of zero, buffer contains the acquired data.
count is the number of samples to be acquired (that is, the number of A/D conversions to be
performed).
Range: 3 through 2
32
– 1 (except Lab and 1200 Series devices, which are limited to
65,535).
sampleRate is the sample rate you want in units of pts/s.
Range: Roughly 0.00153 pts/s through 62,500 pts/s (Lab and 1200 Series devices).
Roughly 0.00153 pts/s through 50,000 pts/s (DAQCard-500/700 and 516 and
LPM devices).
Note If you are using an SCXI-1200 with remote SCXI, the maximum rate will depend
on the baud rate setting and count. Refer to the SCXI-1200 User Manual for more
details.
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 NI-DAQ samples all channels in the scan
sequence. ScanRate must be slightly less than sampleRate/numChans due to a 5 µs delay
interval to the driver.
Lab_ISCAN interval scanning is available on the Lab and 1200 Series
devices only.
Range: 0 and roughly 0.00153 scans/s through 62,500 scans/s.
Note If you are using an SCXI-1200 with remote SCXI, the maximum rate will depend
on the baud rate setting and count. Refer to the SCXI-1200 User Manual for more
details.
A value of 0 disables interval scanning.