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Appendix B
Timing Signal Information
NI PXI-4220 User Manual
B-2
ni.com
DAQ Timing Connections
The timing signals are AI START TRIG, AI REF TRIG, AI SAMP CLK,
AI CONV CLK, AI PAUSE TRIG, AI SAMPLE CLK TIMEBASE,
and AI HOLD COMPLETE.
Posttriggered DAQ allows you to view data that is acquired after a trigger
event is received. Figure B-1 shows a typical posttriggered sequence.
Figure B-1.
Typical Posttriggered Sequence
Pretriggered DAQ allows you to view data that is acquired before the
trigger of interest in addition to data acquired after the trigger. Figure B-2
shows a typical pretriggered sequence.
Figure B-2.
Typical Pretriggered Sequence
1
3
0
4
2
AI START TRIG
AI SAMP CLK
AI CONV CLK
Scan Counter
n/a
0
1
2
3
1
0
2
2
2
AI START TRIG
AI REF TRIG
AI SAMP CLK
AI CONV CLK
Scan Counter
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