Chapter 4
Connecting Signals
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National Instruments Corporation
4-21
the selected edge of TRIG2 is received, the device acquires a fixed number
of scans and the acquisition stops. This mode acquires data both before and
after receiving TRIG2.
As an output, TRIG2 reflects the posttrigger in a pretriggered acquisition
sequence even if another PFI is externally triggering the acquisition.
TRIG2 is not used in posttriggered data acquisition. The output is an active
high pulse with a pulse width of 25 to 50 ns. This output is set to high
impedance at startup.
Figures 4-13 and 4-14 show the timing requirements for TRIG2.
Figure 4-13.
TRIG2 Input Signal Timing
Figure 4-14.
TRIG2 Output Signal Timing
Rising-Edge
Polarity
Falling-Edge
Polarity
t
w
= 10 ns minimum
t
w
t
w
= 25 to 50 ns
t
w