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Chapter 7
Counters
NI 6238/6239 User Manual
AUX
GATE
SOURCE
Counter Value
HW Save Register
Figure 7-20. Single Two-Signal Edge-Separation Measurement
Buffered Two-Signal Edge-Separation Measurement
Buffered and single two-signal edge-separation measurements are similar,
but buffered measurement measures multiple intervals.
The counter counts the number of rising (or falling) edges on the Source
input occurring between an active edge of the Gate signal and an active
edge of the Aux signal. The counter then stores the count in a hardware save
register. On the next active edge of the Gate signal, the counter begins
another measurement. A DMA controller transfers the stored values to host
memory.
Figure 7-21 shows an example of a buffered two-signal edge-separation
measurement.
AUX
GATE
SOURCE
Counter Value
Buffer
Figure 7-21. Buffered Two-Signal Edge-Separation Measurement
For information on connecting counter signals, refer to the
Terminals
section.
Counter
Armed
Measured Interval
0
0
0
0
1
2
1
2
3
3
7-20
3
4
5
6
7
8
8
1
2
3
1
2
3
3
Default Counter
8
8
3
3
3
3
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