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Appendices
NX-series Digital I/O Unit User’s Manual (W521)
A-1 Data Sheet
A
A-1-3 Digital Output Units
Unit name
Transistor Output Unit
Model
NX-OD4256
Number of points
8 points
External connection
terminals
Screwless clamping terminal block (16 ter-
minals)
I/O refreshing method
Switching Synchronous I/O refreshing and Free-Run refreshing
Indicators
TS indicator, output indicator
Internal I/O common
PNP
Rated voltage
24 VDC
Operating load voltage
range
15 to 28.8 VDC
Maximum value of load
current
0.5 A/point, 4 A/NX Unit
Maximum inrush cur-
rent
4.0 A/point, 10 ms max.
Leakage current
0.1 mA max.
Residual voltage
1.5 V max.
ON/OFF response time
0.5 ms max./1.0 ms max.
Dimensions
12 (W) x 100 (H) x 71 (D)
Isolation method
Photocoupler isolation
Insulation resistance
20 MΩ min. between isolated circuits (at
100 VDC)
Dielectric strength
510 VAC between isolated circuits for 1
minute at a leakage current of 5 mA max.
I/O power supply
method
Supply from the NX bus
Current capacity of I/O
power supply terminal
IOG
:
0.5 A/terminal max.
NX Unit power con-
sumption
0.65 W max.
Current consumption
from I/O power supply
30 mA max.
Weight
70 g max.
Circuit layout
Installation orienta-
tion and restrictions
Installation orientation: Possible in 6 orientations.
Restrictions: No restrictions
Terminal connection
diagram
Disconnec-
tion/Short-circuit
detection
Not supported. Protective function With load short-circuit protection.
OUT0 to OUT7
IOG0 to 7
Terminal block
Internal circuits
Short-circuit protection
NX bus
connector
(left)
I/O power supply +
I/O power supply −
I/O power supply +
I/O power supply −
NX bus
connector
(right)
Two-wire type
Three-wire type
24 VDC
Transistor Output
Unit
NX-OD4256
Additional I/O
Power Supply Unit
I/O Power Supply
Connection Unit
A1 B1
A8 B8
OUT7
IOV
IOG
IOV
IOG
IOV
IOG
IOV
IOG
A1 B1
A8 B8
A1 B1
A8 B8
IOV
IOV
IOV
IOV
IOV
IOV
IOV
IOV
IOV
IOV
IOV
IOV
IOV
IOV
IOV
IOV
OUT0
OUT2
OUT4
IOG0
IOG2
IOG4
OUT1
OUT3
OUT5
IOG1
IOG3
IOG6
OUT6
IOG7
IOG5