National Instruments NI 9512 User Manual - page 38
3-10
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Chapter 3
Signal Connections
Figure 3-8.
High-Side Switch Connected to a Sinking Home or Limit
Figure 3-9.
Low-Side Switch Connected to a Sourcing Home or Limit
Encoder Inputs
The encoder inputs provide position and velocity feedback information. The encoder channels
consist of a Phase A, Phase B, and Index input, as described in the following sections. The
NI 9512 and NI 9514 each have a single encoder channel.
The NI 9516 supports two encoder channels that allow for dual-loop feedback, which enhances
system stability and precision and provides backlash compensation. The Encoder 0 channel
consists of a Phase A, a Phase B, and an Index input. The Encoder 1 channel consists of a Phase
A and a Phase B input and does not contain an Index input.
All encoder signals are digitally filtered and provide programmable filter frequencies. The filter
settings are based on the software-programmable maximum velocity rate. Refer to the
NI SoftMotion Module
book of the
LabVIEW Help
for more information about encoder filter
settings.
Encoder Phase A/Phase B
Encoder input channel converts pulses on Phase A and Phase B into 32-bit up/down counter
values. Pulses are generated by optical, magnetic, laser, or electronic devices that provide
two signals, Phase A and Phase B, that are 90 degrees out of phase. The leading phase, A or B,
determines the direction of motion. The four transition states of the relative signal phases
provide distinct pulse edges that are used to determine position.
High-
S
ide
S
witch
NI 951x
NI 951x V
su
p
Limit, Home,
or Digit
a
l Inp
u
t
Config
u
red
For
S
inking
COM
Limit, Home,
or Digit
a
l Inp
u
t
Low-
S
ide
S
witch
COM
NI 951x
Limit, Home,
or Digit
a
l Inp
u
t
NI 951x V
su
p
Config
u
red
For
S
o
u
rcing
Limit, Home,
or Digit
a
l Inp
u
t