Page top


Safety CPU Unit


The Safety CPU Unit controls up to 32 Safety I/O Units.

Regulations and Standards

Certification body Standards
TÜV Rheinland * EN ISO 13849-1: 2008 + AC: 2009
EN ISO 13849-2: 2012
IEC 61508 parts 1-7: 2010
EN 62061: 2005
EN 61131-2: 2007
EN ISO 13850: 2008
EN 60204-1: 2006 + A1: 2009 + AC: 2010
EN 61000-6-2: 2005
EN 61000-6-4: 2007
NFPA 79: 2012
ANSI RIA 15.06-1999
ANSI B11.19-2010
IEC 61326-3-1: 2008
UL cULus: Listed (UL508) and ANSI/ISA 12.12.01

* Certification was received for applications in which OMRON FSoE devices are connected to each other.

The NX-series Safety Control Units allow you to build a safety control system that meets the following standards.

  • Requirements for SIL 3 (Safety Integrity Level 3) in IEC 61508, EN 62061, Safety Standard for Safety Instrumented Systems (Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems)
  • Requirements for PLe (Performance Level e) and for safety category 4 in EN ISO13849-1
The NX-series Safety Control Units are also registered for C-Tick and KC compliance.

General Specification

Item Specification
Enclosure Mounted in a panel (open)
Grounding method Ground to 100 Ω or less.
Ambient operating
0 to 55°C (The upper limit of the ambient operating temperature is
restricted by the installation orientation.)
Ambient operating
10% to 95% (with no condensation or icing)
Atmosphere Must be free from corrosive gases.
Ambient storage
-25 to 70°C (with no condensation or icing)
Altitude 2,000 m max.
Pollution degree 2 or less: Conforms to JIS B3502 and IEC 61131-2.
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 Category II: Conforms to JIS B3502 and IEC 61131-2.
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)
Applicable standards IEC 61508: 2010 SIL 3, EN 62061: 2005 SIL CL3
EN ISO 13849-1, 13849-2: 2008 PL e/Safety Category 4
UL 1998
cULus: Listed UL508, ANSI/ISA 12.12.01
EN 61131-2, C-Tick, KC: KC Registration, NK, LR

Specifications of Individual Units

Safety CPU Unit NX-SL3300/SL3500

Unit name Safety CPU Unit
Model NX-SL3300 NX-SL3500
Maximum number of safety I/O
256 points 1024 points
Program capacity 512 KB 2048 KB
Number of safety master
32 128
I/O refreshing method Free-Run refreshing Free-Run refreshing
External connection terminals None None
Indicators FS indicator, VALID indicator, DEBUG indicator,
TS indicator, and RUN indicator
FS indicator, VALID indicator, DEBUG indicator,
TS indicator, and RUN indicator
Dimensions 30 × 100 × 71 mm (W × H × D)
I/O power supply method Not supplied.
Current capacity of I/O power
supply terminals
No I/O power supply terminals
NX Unit power consumption 0.90 W max.
Current consumption from I/O
power supply
No consumption
Weight 75 g max.
Installation orientation and
Installation orientation: 6 possible orientations
Restrictions: None

Version Information

The combinations that can be used of the unit versions of the Safety Control Units, NJ/NX-series CPU Units, and NX-series EtherCAT Coupler Unit, and the version of the Sysmac Studio

NX Unit Corresponding version *
Model number Unit
Coupler Unit
CPU Units
Coupler Unit
NX-SL3300 1.0 1.1 or later 1.06 or later 1.07 or later --- ---
1.1 1.10 or later 1.0 or later 1.10 or later
NX-SL3500 1.0 1.2 or later 1.07 or later 1.08 or later --- ---
1.1 1.10 or later --- ---

* Some Units do not have all of the versions given in the above table.
  If a Unit does not have the specified version, support is provided by the oldest available version after the specified version.
  Refer to the user’s manuals for the specific Units for the relation between models and versions.