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Operation Theory
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27
Scan_start
ADCONV
3 Scans (PSC_Counter=3)
Scan Interval T=
SI_COUNTER/TimeBase
Acquisition_in_progress
( channel sequences are specified in Channel Gain Queue)
Post Scan Count
3
2
1
0
Figure 9: Scan Timing
There are 4 trigger modes to start the scan acquisition, please refer to
section 4.1.4.2 for more details. The data transfer mode is discussed in
section 4.1.4.3.
Note:
1. The maximum A/D sampling rate is 2MHz for DAQ/PXI-2010, 500kHz
for DAQ/PXI-2005 and 250kHz for DAQ/PXI-2006. Therefore, the
minimum setting of SI_counter is 20 for DAQ/PXI-2010, 80 for
DAQ/PXI-2005 and 160 for DAQ/PXI-2006 while using the internal
TIMEBASE.
2. The SI_counter is a 24-bit counter. Therefore, the maximum scan in-
terval while using an internal TIMEBASE = 2
24
/40M s = 0.419s.
4.1.4.2 Trigger Modes
DAQ/PXI-20XX provides 4 trigger sources (internal software trigger, ex-
ternal analog trigger, external digital trigger or SSI trigger signals). You
must select one of them as the source of the trigger event. A trigger event
occurs when the specified condition is detected on the selected trigger
source (For example, a rising edge on the external digital trigger input).
Please refer to section 4.6 for more information about SSI signals.