Chapter 4
General-Purpose Counter/Timer
DAQ-STC Technical Reference Manual
4-4
©
National Instruments Corporation
4.4.1.1 Simple Event Counting
In simple event counting, the counter counts the number of pulses that occur on the
G_SOURCE signal after the software arm. Software can read the counter contents at any time
without disturbing the counting process. Figure 4-2 shows an example of simple event
counting where the counter counts five events on G_SOURCE.
Figure 4-2.
Simple Event Counting
4.4.1.2 Simple Gated-Event Counting
Simple gated-event counting is similar to simple event counting except that the counting
process is gated; that is, halted and resumed via G_GATE. When G_GATE is active, the
counter counts pulses that occur on the G_SOURCE signal after the software arm. When
G_GATE is inactive, the counter retains the current count value. Figure 4-3 shows an example
of simple gated-event counting where the gate action allows the counter to count only five of
the pulses on G_SOURCE.
Figure 4-3.
Simple Gated-Event Counting
4.4.1.3 Buffered Noncumulative Event Counting
Buffered noncumulative event counting is similar to simple event counting except that there
are multiple counting intervals. The G_GATE signal indicates the boundary between
consecutive counting intervals. The counter counts the number of pulses that occur on the
Software Arm
G_SOURCE
Counter Value
1
0
5
4
3
2
Software Arm
G_SOURCE
G_GATE
Counter Value
1
0
5
4
3
2
