© National Instruments
|
4-11
NI 17xx User Manual
National Instruments does
not
recommend the use of single-ended encoders with the smart
camera. This configuration would require the ground for a single-ended encoder to be connected
to the COM pin of the smart camera, and the PhaseA- and PhaseB- signals would be left
unconnected. In this configuration, the system is susceptible to significant noise that would be
eliminated by using a differential encoder.
Shielded encoder cables are recommended for all applications. Unshielded cables are more
susceptible to noise and can corrupt the encoder signals.
Refer to the
External Trigger
section of Chapter 6,
Image Acquisition
, for information about
using a quadrature encoder to delay a trigger.
Figure 4-
8
shows an example of connecting the quadrature encoder differential line drivers.
Figure 4-8.
Connecting Differential Line Drivers
Ph
as
e A+
Ph
as
e A–
Ph
as
e A–
Ph
as
e A
Ph
as
e B+
Ph
as
e B–
Ph
as
e B–
Ph
as
e B
Encoder
NI
17xx
Twi
s
ted
P
a
ir
Twi
s
ted
P
a
ir
