Chapter 7
Counters
X Series User Manual
7-26
ni.com
co
u
nter armed event; that is, the sample clock does not reset the co
u
nter.
Yo
u
can ro
u
te the co
u
nter sample clock to the Gate inp
u
t of the co
u
nter.
Yo
u
can config
u
re the co
u
nter to sample on the rising or falling edge of the
sample clock.
Fig
u
re 7-23 shows an example of a b
u
ffered X1 position meas
u
rement.
Figure 7-23.
Buffered Position Measurement
Hardware-Timed Single Point Position Measurement
A hardware-timed single point (HWTSP) position meas
u
rement has the
same behavior as a b
u
ffered (sample clock) position meas
u
rement.
Note
(NI USB-634
x
/635
x
/636
x
Devices)
X Series USB devices do not s
u
pport
hardware-timed single point (HWTSP) operations.
For information abo
u
t connecting co
u
nter signals, refer to the
Default
Counter/Timer Pinouts
section.
Two-Signal Edge-Separation Measurement
Two-signal edge-separation meas
u
rement is similar to p
u
lse-width
meas
u
rement, except that there are two meas
u
rement signals—A
u
x and
Gate. An active edge on the A
u
x inp
u
t starts the co
u
nting and an active
edge on the Gate inp
u
t stops the co
u
nting. Yo
u
m
u
st arm a co
u
nter to begin
a two edge separation meas
u
rement.
After the co
u
nter has been armed and an active edge occ
u
rs on the A
u
x
inp
u
t, the co
u
nter co
u
nts the n
u
mber of rising (or falling) edges on the
So
u
rce. The co
u
nter ignores additional edges on the A
u
x inp
u
t.
1
3
1
Ch A
Ch B
3
1
0
2
4
Co
u
nt
B
u
ffer
Sa
mple Clock
(
Sa
mple on Ri
s
ing Edge)
Co
u
nter
Armed
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