©
National Instruments Corp.
7
NI 9478 Operating Instructions and Specifications
Each channel of the NI 9478 has a DO pin to which yo
u
can
connect the load yo
u
want to control. Each channel also has a COM
pin. National Instr
u
ments recommends yo
u
provide independent
COM wiring for each channel to minimize c
u
rrent flow in the
COM wiring. The COM pins are all connected together internally.
Yo
u
m
u
st connect an external power s
u
pply to the NI 9478. This
power s
u
pply provides the c
u
rrent for the devices yo
u
connect to
the mod
u
le. Connect the positive lead of the power s
u
pply to V
s
u
p
and the negative lead of the power s
u
pply to COM.
Caution
Do not remove or insert mod
u
les if the external
power s
u
pply connected to the V
s
u
p
pin is powered on.
The NI 9478 has c
u
rrent sinking o
u
tp
u
ts, meaning the DO pin is
driven to COM when the channel is t
u
rned on.
Yo
u
can directly connect the NI 9478 to a variety of ind
u
strial
devices s
u
ch as solenoids, motors, act
u
ators, relays, and lamps.
Make s
u
re the devices yo
u
connect to the NI 9478 are compatible
with the o
u
tp
u
t specifications of the mod
u
le. Refer to the
section for more information abo
u
t the o
u
tp
u
t
specifications.
