Single Point (On-Demand) Edge Counting - National Instruments DAQ X Series User Manual

Chapter 7 Counters
Refer to the following sections for more information about X Series edge
counting options:
•
•

Single Point (On-Demand) Edge Counting

With single point (on-demand) edge counting, the counter counts the
number of edges on the Source input after the counter is armed. On-demand
refers to the fact that software can read the counter contents at any time
without disturbing the counting process. Figure 7-2 shows an example of
single point edge counting.
You also can use a pause trigger to pause (or gate) the counter. When the
pause trigger is active, the counter ignores edges on its Source input. When
the pause trigger is inactive, the counter counts edges normally.
You can route the pause trigger to the Gate input of the counter. You can
configure the counter to pause counting when the pause trigger is high or
when it is low. Figure 7-3 shows an example of on-demand edge counting
with a pause trigger.
X Series User Manual
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Single Point (On-Demand) Edge Counting
Buffered (Sample Clock) Edge Counting
Counter Armed
SOURCE
Counter Value 0 1
Figure 7-2. Single Point (On-Demand) Edge Counting
Counter Armed
Pause Trigger
(Pause When Low)
SOURCE
0 0
Counter Value
Figure 7-3. Single Point (On-Demand) Edge Counting with Pause Trigger
7-4
2 3 4 5
1 2 3 4 5
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