Chapter 8
Counters
©
National Instruments Corporation
8-39
Figure 8-35.
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
