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

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Chapter 8 Counters
© National Instruments Corporation 8-37 NI USB-621x User Manual
Figure 8-33. Duplicate Count Prevention Example
Even if the So u rce p u lses are long, the co u nter increments only once for
each So u rce p u lse.
Normally, the co u nter val u e and Co u nter n Internal O u tp u t signals change
synchrono u sly to the So u rce signal. With d u plicate co u nt prevention, the
co u nter val u e and Co u nter n Internal O u tp u t signals change synchrono u sly
to the 80 MHz Timebase.
Enabling Duplicate Count Prevention in NI-DAQmx
D u plicate co u nt prevention is a u tomatically u sed with USB-621 x devices.
Disabling d u plicate co u nt prevention is not s u pported.
G a te
0
7 7
6 7 0 1
Co u nter detect s
ri s ing G a te edge.
S o u rce
Co u nter V a l u e
B u ffer
Co u nter v a l u e
increment s only
one time for e a ch
S o u rce p u l s e.
80 MHz Time bas e