Datasheet

12 Remote I/O
Digital output unit
Item Specifications
Model NX-OD3121 NX-OD4121 NX-OD5121 NX-OD3153 NX-OD3256 NX-OD4256 NX-OD5256 NX-OD3268 NX-OD3257
Name Transistor output unit
Internal I/O common NPN PNP
Capacity 4 points 8 points 16 points 4 points 4 points 8 points 16 points 4 points 4 points
Rated voltage 12 to 24 VDC 24 VDC
Operating load voltage 10.2 to 28.8 VDC 15 to 28.8 VDC
Maximum value of load
current
0.5 A/point,
2 A/NX unit
0.5 A/point, 4 A/NX unit 0.5 A/point,
2 A/NX unit
0.5 A/point,
2 A/NX unit
0.5 A/point, 4 A/NX unit 2 A/point,
8 A/NX unit
0.5 A/point,
2 A/NX unit
Maximum inrush current 4.0 A/point, 10 ms max.
Leakage current 0.1 mA max.
Residual voltage 1.5 V max.
ON/OFF response time 0.1 ms max./0.8 ms max. 300 ns max. 0.5 ms max./1.0 ms max. 300 ns max.
Dielectric strength 510 VAC between isolated circuits for 1 minute at a leakage current of 5 mA max.
Insulation resistance 20 M min. between isolated circuits (at 100 VDC)
Isolation method Photocoupler isolation Digital isolator Photocoupler isolation Digital isolator
Unit power consumption 0.55 W max. 0.55 W max. 0.65 W max. 0.50 W max. 0.55 W max. 0.65 W max. 0.70 W max. 0.50 W max. 0.50 W max.
I/O power supply method Supply from the NX bus Supply from
external
source
Supply from
the NX bus
I/O current consumption 10 mA max. 10 mA max. 20 mA max. 30 mA max. 20 mA max. 30 mA max. 40 mA max. 20 mA max. 40 mA max.
Current capacity of I/O
power supply terminal
0.5 A/terminal max. Without I/O
power supply
terminals
0.5 A/terminal
max.
0.5 A/terminal max. Without I/O
power supply
terminals
IOV/IOG: 2 A/
terminal max.
COM/0V: 4A/
terminal max.
0.5 A/terminal
max.
I/O refreshing method Switching synchronous I/O refreshing and free-run refreshing
Terminal block type Screwless
push-in termi-
nal
12 terminals
(A + B)
Screwless
push-in termi-
nal
16 terminals
(A + B)
Screwless
push-in termi-
nal
16 terminals
(A + B)
Screwless
push-in termi-
nal
12 terminals
(A + B)
Screwless
push-in termi-
nal
12 terminals
(A + B)
Screwless
push-in termi-
nal
16 terminals
(A + B)
Screwless
push-in termi-
nal
16 terminals
(A + B)
Screwless
push-in termi-
nal
16 terminals
(A + B)
Screwless
push-in termi-
nal
12 terminals
(A + B)
Dimensions (W x H x D) 12 × 100 × 71 mm
Weight 70 g max.
Disconnection/
short-circuit detection
Not supported
Protective function Not supported With load short-circuit protection
IOV
IOG
IOV
IOG
IOV
IOG
IOV
IOG
OUT0
IOG0
IOV2
IOV0
A1 B1
A8 B8
OUT2
IOG2
OUT1
IOG1
IOV3
IOV1
OUT3
IOG3
Two-wire type
Three-wire type
A1 B1
A8 B8
24 VDC
Terminal wiring
NX-OD3121
Circuit layout
NX-OD3121
OUT0 to OUT3
IOV0 to 3
IOG0 to 3
Terminal block
I/O power supply +
I/O power supply

Internal circuits
I/O power supply +
I/O power supply

OUT0 to OUT3
This unit uses a push-pull output circuit.
IOV0 to 3
IOG0 to 3
Terminal block
I/O power supply +
I/O power supply 
Internal circuits
Isolation circuit
I/O power supply +
I/O power supply 
Drive circuit
NX-OD3153
NX-OD3153
IOV
IOG
IOV
IOG
IOV
IOG
IOV
IOG
OUT0
IOG0
IOV2
IOV0
A1 B1
A8 B8
OUT2
IOG2
OUT1
IOG1
IOV3
IOV1
OUT3
IOG3
Two-wire type
Three-wire type
A1 B1
A8 B8
24 VDC
NX bus
connector
(left)
NX bus
connector
(right)
NX bus
connector
(left)
NX bus
connector
(right)
Additional I/O
power supply unit
Transistor output
unit
NX-OD3121
Additional I/O
power supply unit
Transistor output
unit
NX-OD3153