Menu
Industrial Automation
NX-SI / SO
Safety I/O Unit
Build a simple and flexible safety system
Related Contents
Application Solutions
- Features
- Lineup
- Specifications
- Dimensions
- Catalog / Manual / CAD / Software
last update: June 23, 2025
Regulations and Standards
Safety I/O Units NX-SI/SO
| Certification body | Standards |
|---|---|
| TÜV Rheinland *1 | • EN ISO 13849-1
• EN ISO 13849-2 • IEC 61508 parts 1-7 • IEC/EN 61131-2 • IEC 61326-3-1 |
| UL | • NRAG (UL 508 and ANSI/ISA 12.12.01)
• NRAG7 (CSA C22.2 No. 142 and CSA C22.2 No. 213) |
| Shipbuilding Standards | NK, LK |
*1 Using the NX-series Safety I/O Units in conjunction with the NX-series Safety CPU Unit allows you to build a safety control
system that meets the following standards:
• Requirements for SIL 3 in IEC 61508
• Requirements for PLe and Category 4 in EN ISO 13849-1
The NX-series Safety I/O Units are also registered for RCM and KC compliance.
system that meets the following standards:
• Requirements for SIL 3 in IEC 61508
• Requirements for PLe and Category 4 in EN ISO 13849-1
The NX-series Safety I/O Units are also registered for RCM and KC compliance.
General Specifications
| Item | Specification | |
|---|---|---|
| Enclosure | Mounted in a panel (open) | |
| Grounding method | Ground to 100 Ω or less. | |
| Operating
environment |
Ambient operating temperature | 0 to 55°C (The upper limit of the ambient operating temperature
is restricted by the installation orientation.) |
| Ambient operating humidity | 10% to 95% (with no condensation or icing) | |
| Atmosphere | Must be free from corrosive gases. | |
| Ambient storage temperature | -25 to 70°C (with no condensation or icing) | |
| Altitude | 2,000 m max. | |
| Pollution degree | 2 or less. | |
| Noise immunity | Conforms to IEC 61131-2.
2 kV on power supply line (Conforms to IEC 61000-4-4.) |
|
| Insulation class | Class III (SELV) | |
| Overvoltage category | II | |
| EMC immunity level | Zone B | |
| Vibration resistance | Conforms to IEC 60068-2-6.
5 to 8.4 Hz with 3.5-mm amplitude, 8.4 to 150 Hz, acceleration of 9.8 m/s2, 100 minutes each in X, Y, and Z directions (10 sweeps of 10 min each = 100 min total) |
|
| Shock resistance | Conforms to IEC 60068-2-27.
147 m/s2, 3 times each in X, Y, and Z directions |
|
| Insulation resistance | 20 MΩ between isolated circuits (at 100 VDC) | |
| Dielectric strength | 510 VAC for 1 min between isolated circuits,
leakage current: 5 mA max. |
|
| Installation method | DIN Track (IEC 60715 TH35-7.5/TH35-15) | |
Unit Specifications
Safety Input Units NX-SIH400/SID800
| Unit name | Safety Input Unit | |
|---|---|---|
| Model | NX-SIH400 | NX-SID800 |
| Number of safety
input points |
4 points | 8 points |
| Number of test
output points |
2 points | 2 points |
| Internal I/O common | PNP (sinking inputs) | |
| Rated input voltage | 24 VDC (20.4 to 28.8 VDC) | |
| OMRON special
safety input devices |
Can be connected. | Cannot be connected. |
| Number of safety
slave connections |
1 | |
| I/O refreshing method | Free-Run refreshing | |
| External connection
terminals |
Screwless clamping terminal block (8
terminals) |
Screwless clamping terminal block (16
terminals) |
| Indicators |  |
 |
| Safety input current | 4.5 mA typical | 3.0 mA typical |
| Safety input
ON voltage |
11 VDC min. | 15 VDC min. |
| Safety input OFF
voltage/OFF current |
5 VDC max., 1 mA max. | |
| Test output type | Sourcing outputs (PNP) | |
| Test output load
current |
25 mA max. | 50 mA max. |
| Test output
residual voltage |
1.2 V max. (Between IOV and all output terminals) | |
| Test output
leakage current |
0.1 mA max. | |
| Dimensions | 12 × 100 × 71 mm (W × H × D) | |
| Isolation method | Photocoupler isolation | |
| Insulation resistance | 20 MΩ min. between isolated circuits (at 100 VDC) | |
| Dielectric strength | 510 VAC for 1 min between isolated circuits, leakage current: 5 mA max. | |
| I/O power supply
method |
Power supplied from the NX bus | |
| Current capacity of
I/O power supply terminals |
No applicable terminals. | |
| NX Unit
power consumption |
• Connected to a CPU Unit or a
Communication Control Unit *1 1.10 W max. • Connected to a Communications Coupler Unit *2 0.70 W max. |
• Connected to a CPU Unit or a
Communication Control Unit *1 1.10 W max. • Connected to a Communications Coupler Unit *2 0.75 W max. |
| Current consumption
from I/O power supply |
20 mA max. | |
| Weight | 70 g max. | |
| Circuit layout |  |
 |
| Terminal connection
diagram |
Si0 to Si3: Safety input terminals
T0 and T1: Test output terminals  |
Si0 to Si7: Safety input terminals
T0 and T1: Test output terminals  |
| Installation orientation
and restrictions |
Installation orientation:
• Connected to a CPU Unit or a Communication Control Unit *1 Possible in the upright installation orientation. • Connected to a Communications Coupler Unit *2 6 possible orientations. Restrictions: Maximum ambient temperature is 50ºC for any orientation other than upright installation. |
|
| Protective functions | Overvoltage protection circuit and short detection (test outputs) | |
*1 The NX102 CPU Unit, NX502 CPU Unit, and NX-CSG Communication Control Unit can be connected. It cannot be connected to the NX1P2 CPU unit.
*2 The NX-ECC20 EtherCAT Coupler Unit and NX-EIC202 EtherNet/IP Coupler Unit can be connected.
Safety Output Units NX-SOH200/SOD400
| Unit name | Safety Output Unit | |
|---|---|---|
| Model | NX-SOH200 | NX-SOD400 |
| Number of safety
output points |
2 points | 4 points |
| Internal I/O common | PNP (sourcing outputs) | |
| Maximum load
current |
2.0 A/point
4.0 A/Unit at 40°C 2.5 A/Unit at 55°C The maximum load current depends on the installation orientation and ambient temperature. See Installation orientation and restrictions. |
0.5 A/point and 2.0 A/Unit |
| Rated voltage | 24 VDC (20.4 to 28.8 VDC) | |
| Number of safety
slave connections |
1 | |
| I/O refreshing method | Free-Run refreshing | |
| External connection
terminals |
Screwless clamping terminal block (8 terminals) | |
| Indicators |  |
 |
| Safety output ON
residual voltage |
1.2 V max. (Between IOV and all output terminals) | |
| Safety output OFF
residual voltage |
2 V max. (Between IOG and all output terminals) | |
| Safety output leakage
current |
0.1 mA max. | |
| Dimensions | 12 × 100 × 71 mm (W × H × D) | |
| Isolation method | Photocoupler isolation | |
| Insulation resistance | 20 MΩ min. between isolated circuits (at 100 VDC) | |
| Dielectric strength | 510 VAC for 1 min between isolated circuits, leakage current: 5 mA max. | |
| I/O power supply
method |
Power supplied from the NX bus | |
| Current capacity of
I/O power supply terminals |
IOG: 2 A max./terminal | IOG (A3 and B3): 2 A max./terminal
IOG (A7 and B7): 0.5 A max./terminal |
| NX Unit power
consumption |
• Connected to a CPU Unit or a
Communication Control Unit *1 1.05 W max. • Connected to a Communications Coupler Unit *2 0.70 W max. |
• Connected to a CPU Unit or a
Communication Control Unit *1 1.10 W max. • Connected to a Communications Coupler Unit *2 0.75 W max. |
| Current consumption
from I/O power supply |
40 mA max. | 60 mA max. |
| Weight | 65 g max. | |
| Circuit layout |  |
 |
| Terminal connection
diagram |
So0 and So1: Safety output terminals
IOG: I/O power supply 0 V 
Refer to User's manual (Cat.No.Z930) for details. |
So0 to So3: Safety output terminals
IOG: I/O power supply 0 V 
Refer to User's manual (Cat.No.Z930) for details. |
| Installation
orientation and restrictions |
Installation orientation:
• Connected to a CPU Unit or a Communication Control Unit *1 Possible in the upright installation orientation. • Connected to a Communications Coupler Unit *2 6 possible orientations Restrictions: For upright installation, the ambient temperature is restricted as shown below depending on the total Unit load current. 
For all installation orientations other than upright installation, the ambient temperature is restricted as shown below according to the total Unit load current.  |
Installation orientation:
• Connected to a CPU Unit or a Communication Control Unit *1 Possible in the upright installation orientation. • Connected to a Communications Coupler Unit *2 6 possible orientations Restrictions: None |
| Protective functions | Overvoltage protection circuit and short detection | |
*1 The NX102 CPU Unit, NX502 CPU Unit, and NX-CSG Communication Control Unit can be connected. The NX1P2 CPU Unit cannot be connected.
*2 The NX-ECC20 EtherCAT Coupler Unit and NX-EIC202 EtherNet/IP Coupler Unit can be connected.
*2 The NX-ECC20 EtherCAT Coupler Unit and NX-EIC202 EtherNet/IP Coupler Unit can be connected.
Version Information
The following table shows the possible combinations of versions of NX-series Safety I/O Units, CPU Units, Communications Coupler Units, Communication Control Unit, and Sysmac Studio. Available functions that are related to safety control vary depending on the versions of the units and Sysmac Studio. Refer to the NX-series Safety Control Unit User's Manual (Cat. No. Z930) for details.
| Safety Control Unit
model and version |
NX bus master:
NX102 CPU Unit |
NX bus master:
NX502 CPU Unit |
NX bus master:
EtherCAT Coupler Unit |
NX bus master:
EtherNet/IP Coupler Unit |
||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Model | Unit
version |
NX102-
[][][][] |
Sysmac
Studio |
NX502-
[][][][] |
Sysmac
Studio |
Commu-
nications Coupler Unit NX- ECC20[] |
NJ/NX1P/
NX7 CPU Unit *1 |
Sysmac
Studio |
Commu-
nications Coupler Unit NX- EIC202 |
Sysmac
Studio |
| NX-SIH400 | Ver.1.0 | Ver.1.30
or later |
Ver.1.22
or higher |
Ver.1.60
or later |
Ver.1.54
or higher |
Ver.1.2
or later |
Ver.1.06
or later |
Ver.1.07
or higher |
--- | --- |
| Ver.1.1 | Ver.1.10
or higher |
Ver.1.0
or later |
Ver.1.10
or higher |
|||||||
| NX-SID800 | Ver.1.0 | Ver.1.30
or later |
Ver.1.22
or higher |
Ver.1.60
or later |
Ver.1.54
or higher |
Ver.1.1
or later |
Ver.1.06
or later |
Ver.1.07
or higher |
Ver.1.0
or later |
Ver.1.10
or higher |
| NX-SOH200 | Ver.1.0 | Ver.1.30
or later |
Ver.1.22
or higher |
Ver.1.60
or later |
Ver.1.54
or higher |
Ver.1.1
or later |
Ver.1.06
or later |
Ver.1.07
or higher |
Ver.1.0
or later |
Ver.1.10
or higher |
| NX-SOD400 | Ver.1.0 | Ver.1.30
or later |
Ver.1.22
or higher |
Ver.1.60
or later |
Ver.1.54
or higher |
Ver.1.1
or later |
Ver.1.06
or later |
Ver.1.07
or higher |
Ver.1.0
or later |
Ver.1.10
or higher |
*1 This is version information when the NJ/NX1P/NX7 CPU Unit is used as the EtherCAT master in the system. The Safety
Control Unit cannot be connected directly to these CPU Units.
Control Unit cannot be connected directly to these CPU Units.
last update: June 23, 2025
Top of page
Products
Menu
About Us
Menu
Solutions
Menu
Privacy
Menu
Services
Menu
Resources
Menu
© Copyright OMRON Corporation 2000-2020. All Rights Reserved.