©
National Instruments Corporation
3
NI 177x Power and I/O Acessory User Guide
4.
Connect the power supply to the 24 V IN connector on the Power and I/O Accessory.
5.
Connect the power supply to a power source.
Testing and Replacing Fuses
The Power and I/O Accessory has seven replaceable fuses. For fuse and spare fuse locations,
refer to Figure 2. For a description of the included fuses, refer to Table 1.
Figure 2.
Fuse Locations
You can use a handheld DMM to verify the continuity of a fuse.
Complete the following steps to replace a blown fuse:
1.
Unplug the power supply.
2.
Remove all signal wires and cables from the Power and I/O Accessory.
3.
Remove a side panel. Use a Phillips head screwdriver to remove the 2 retaining screws.
4.
Slide the circuit board out.
5.
Replace any blown fuses with an equivalent replacement fuse. Replacement fuses are
labelled as SPARE on the circuit board.
Table 1.
Power and I/O Accessory Fuses
Protected Signal
Replacement
Fuse Quantity
Littelfuse
Part Number
Fuse Description
24 V IN
1
0448002.MR
2 A, 125V lead-free very fast-acting
NANO
2
subminiature ceramic surface
mount fuse, 6.10 × 2.69 mm
RS232, LED DRV,
OUT0, OUT1,
OUT2, OUT3
3
0448001.MR
1 A, 125V lead-free very fast-acting
NANO
2
subminiature ceramic surface
mount fuse, 6.10 × 2.69 mm
24V IN
4V IN
2A
2A
PCB476R0
CB476R0
SPARE FUSES
PARE FUSES 1A
AI
I –5–0
94V-0
4V-0
27-11
RS232 1A
S232 1A
SPARE
PARE
2A
2A
L
ED DR
V 1A
E
D
D
R
V
1
A
O
U
T3 1A
U
T
3
1
A
O
U
T2 1A
U
T
2
1
A
O
U
T1 1A
U
T
1
1
A
O
U
T0 1A
U
T
0
1
A
