National Instruments Data Acquisition Device NI USB-621x, Руководство пользователя

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Chapter 8 Counters
© National Instruments Corporation 8-21 NI USB-621x User Manual
Fig u re 8-22 shows a generation of a p u lse with a p u lse delay of fo u r and a
p u lse width of three ( u sing the rising edge of So u rce).
Figure 8-22. Single Pulse Generation with Start Trigger
Retriggerable Single Pulse Generation
The co u nter can o u tp u t a single p u lse in response to each p u lse on a
hardware Start Trigger signal. The p u lses appear on the Co u nter n Internal
O u tp u t signal of the co u nter.
Yo u can ro u te the Start Trigger signal to the Gate inp u t of the co u nter. Yo u
can specify a delay from the Start Trigger to the beginning of each p u lse.
Yo u also can specify the p u lse width. The delay and p u lse width are
meas u red in terms of a n u mber of active edges of the So u rce inp u t.
The co u nter ignores the Gate inp u t while a p u lse generation is in progress.
After the p u lse generation is finished, the co u nter waits for another Start
Trigger signal to begin another p u lse generation.
Fig u re 8-23 shows a generation of two p u lses with a p u lse delay of five and
a p u lse width of three ( u sing the rising edge of So u rce).
Figure 8-23. Retriggerable Single Pulse Generation
For information abo u t connecting co u nter signals, refer to the Default
Counter/Timer Pinouts section.
S OURCE
GATE
( S t a rt Trigger)
OUT
S OURCE
GATE
( S t a rt Trigger)
OUT