©
National Instruments Corp.
13
NI 9512 Operating Instructions and Specifications
Many stepper drive man
u
fact
u
rers offer opto-isolated inp
u
ts for
Step (CW)/Direction (CCW) signals. When connecting to
opto-isolated inp
u
ts, config
u
re the Step o
u
tp
u
t type to
single-ended, connect the NI 9512 Step+ o
u
tp
u
t to the negative
(cathode) side of the optoco
u
pler inp
u
t, and leave the Step– o
u
tp
u
t
on the NI 9512 disconnected. Connect the positive (anode) side of
the drive inp
u
t to a s
u
pply as specified by the drive man
u
fact
u
rer.
Fig
u
re 6 shows a single-ended connection example.
Figure 6.
Opto-Isolated Step and Direction Output Connection
The encoder channel consists of a Phase A, a Phase B, and an Index
inp
u
t. The NI 9512 s
u
pports RS-422 differential and single-ended
inp
u
ts for Phase A, Phase B, and Index signals, and provides a
+5 V o
u
tp
u
t for encoder power. National Instr
u
ments strongly
recommends yo
u
u
se encoders with differential line driver o
u
tp
u
ts
for optimized noise imm
u
nity and improved acc
u
racy in all
NI 9512
Step+/Dir+
Drive
Step+/Dir+
Step–/Dir–
+5 V
No Connection
Step–/Dir–