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3-9
You can specify whether the measurement acquisition begins taking posttrigger samples on the
rising edge or falling edge of AI Reference Trigger.
Using an Analog Source
When you use an analog trigger source, the acquisition begins taking posttrigger samples on the
rising edge of the Analog Comparison Event signal. For more information, refer to the
section.
Routing AI Reference Trigger to an Output Terminal
You can route the AI Reference Trigger signal to an PXI_TRIG <0..7> or PXIe_DSTARC
terminal.
All PFI terminals are inputs only and cannot be used to export the AI Reference Trigger.
AI Pause Trigger Signal
Use the AI Pause Trigger (ai/PauseTrigger) signal to pause and resume a measurement
acquisition. When using the internal sample clock, the sample clock is halted while the pause
trigger signal is active and resumes when the signal is inactive. When using an external free
running sample clock, the AI Sample Clock edges are masked by the pause trigger. You can
program the active level of the pause trigger to be high or low. Figure 3-7 shows an example of
using the AI Pause Trigger with an internal or external sample clock. In Figure 3-7, T represents
the period, and A represents the unknown time between the sample clock active edge and the
pause trigger.
Figure 3-7.
Halt (Internal Clock) and Free Running (External Clock)
AI
Sa
mple Clock
AI P
aus
e Trigger
T
A
AI Extern
a
l
Sa
mple Clock
AI P
aus
e Trigger
H
a
lt. U
s
ed on Intern
a
l Clock
Free R
u
nning. U
s
ed on Extern
a
l Clock
T – A
AI
Sa
mple Clock
