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Safety CPU Unit


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

Regulations and Standards

NX-series Safety Control Units NX-SL3/SI/SO

Certification body Standards
TÜV Rheinland * • EN ISO 13849-1
• EN ISO 13849-2
• IEC 61508 parts 1-7
• IEC/EN 62061
• 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)

* The FSoE was certified 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, (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 RCM, EAC, and KC compliance.

General Specifications

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.
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
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)

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 points 256 points 1024 points
Program capacity 512 KB 2048 KB
Number of safety master connections 32 128
I/O refreshing method Free-Run refreshing Free-Run refreshing
External connection terminals None None
Indicators [FS] LED, [VALID] LED, [DEBUG] LED,
Dimensions 30 × 100 × 71 mm (W × H × D)
I/O power supply method Not supplied.
Current capacity of I/O power supply
No I/O power supply terminals
NX Unit power consumption *1 • Connected to a CPU Unit
 1.25 W max.
• Connected to a Communications Coupler Unit
 0.90 W max.
Current consumption from I/O power
No consumption
Weight 75 g max.
Installation orientation and
Installation orientation:
• Connected to a CPU Unit *2
 Possible in the upright installation orientation.
• Connected to a Communications Coupler Unit
 Six possible orientations.
Restriction: None

*1 The cable length for the Units that supply power to the corresponding Unit must be up to 20 m.
*2 Only NX102 CPU Units can be connected. NX1P2 CPU Units cannot be connected.

Function Specifications

Item Function
Safety I/O Settings You make a setting for safety process data communications and
connection with safety I/O devices.
Safety Process Data
You select Safety I/O Units to perform safety process data
communications (FSoE communications) and make necessary
Safety Device
Allocation Settings
You set the connection between Safety I/O Units and safety
EtherNet/IP Safety Connection
Settings *1
You can register target devices of EtherNet/IP Safety network and
configure the connection settings.
Standard I/O
Exposed Variable
You set whether to expose global variables of the Safety CPU Unit.
The values of exposed variables can be referenced from NJ/NX-
series CPU Units and NY-series Industrial PCs.
Standard Process
Communications *2
You set the devices and ports of the Standard I/O Units for the
exposed variables of the Safety CPU Unit.
Safety Task Settings You define the execution cycle and timing of the safety task and
programs to be executed in the task.
Assigning Programs You assign safety programs to execute to the task.
I/O Map Settings The ports of Safety I/O Units used in safety process data
communications are displayed. You assign device variables used
in safety programs to the I/O ports.
Instruction List (Toolbox) A hierarchy of the functions and function blocks that you can use
is displayed in the Toolbox. You can drag the required functions
and function blocks onto the FBD editor to insert it to a safety
FBD Programming You connect variables, functions, and function blocks with
connecting lines to build networks. The FBD editor is used to enter
Adding FBD Networks You create FBD networks on the FBD editor to create algorithms.
Inserting and
Deleting Functions
and Function blocks
You insert and delete functions and function blocks on the FBD
Entry Assistance When you enter functions, function blocks, or parameters, each
character that you enter from the keyboard narrows the list of
candidates that is displayed for selection.
Commenting Out
FBD Networks
You can comment out each FBD network. When a network is
commented out, it is no longer executed.
Converting Programs
into Function Blocks
You can convert the safety program into user-defined function
Automatic Programming *1 A safety programs can be automatically generated from input and
output signals and expected values of the program.
Creating Variables You create variables used in safety programs in the global or local
variable table.
User-defined Function Blocks You create user-defined function blocks.
Help Reference *3 You can display the user-defined function block help with the
popup menu or shortcut key.
Export/Import POUs can be exported and imported.
Programs *4 You can export/import POUs.
Function Blocks *3
You can export/import user-defined function blocks.
Searching and Replacing You can search for and replace strings in the variable tables,
programs, and function blocks of a Safety CPU Unit.
Debugging Monitoring Variables are monitored during safety program execution. You can
monitor the present values of device variables assigned to Safety
I/O Units and user-defined variables. The values can be monitored
on the FBD editor or Watch Tab Page.
Changing the Present Values of
You can change the present values of user-defined variables and
device variables as required. You can do this on the FBD editor or
Watch Tab Page.
Forced Refreshing The inputs from external devices and outputs to external devices
are refreshed with a specified value on the Sysmac Studio. The
specified value is retained even if the value of the variable is
overwritten from the user program.
You can use forced refreshing on the FBD editor or Watch Tab
Offline Debugging *5 You can check if the control program logic works as designed in
advance using a special debugging function for the Simulator
without connecting online with the Safety CPU Unit.
Initial Value Settings
You can set the initial values of variables when you start execution
of simulation.
Feedback Settings
You can set input status that is linked to changes in output status
when simulator is running.
Simple Automatic
Test *7
You can check that expected values of the outputs to the inputs of
the program are designed as intended using the Simulator
functions of the Safety CPU Unit.
User Memory Usage Monitor *6 The memory usage of the safety control system and usage of
safety network such as I/O data size are displayed.
Debugging Online Functional Test *1 This function helps you to check the safety functional operation of
the safety system.
You can produce output device operation relative to the input and
check whether the system operates as expected. It is possible to
output the check results.
Safety Safety Validation You append the "safety-validated" information to a safety program
when you can ensure safety of the program after you complete
Changing Operating Mode There are four operating modes; PROGRAM mode, DEBUG mode
(STOPPED), DEBUG mode (RUN), and RUN mode. The RUN
mode can be selected only for the validated safety programs.
Generating Safety Data Logging
Settings File *1
Settings to use the safety data logging function can be generated
as a file.
Generating Safety Unit Restore
File *1
A file of safety program and settings to be transferred to the Safety
CPU Unit using an SD memory card is generated for Safety Unit
Restore function.
of Incorrect
Setting the Node
You set a unique name for each Safety CPU Unit to confirm that
you operate the correct Safety CPU Unit.
of Incorrect
Safety Password You can prevent unauthorized access to safety functions of Safety
CPU Units by setting a safety password for online operations that
affect the safety functions.
of Theft of
Data Protection
(Programs) *4
You can set passwords for individual programs to prohibit
displaying or changing them.
Data Protection
Function Blocks) *3
You can set passwords for individual user-defined function blocks
to prohibit displaying or changing them.

Note: Supported only by the Sysmac Studio version 1.07 or higher.
*1. Supported only by the Sysmac Studio version 1.24 or higher.
*2. Supported if the EtherNet/IP Coupler is selected with Sysmac Studio version 1.11 or higher.
*3. Supported only by the Sysmac Studio version 1.12 or higher.
*4. Supported only by the Sysmac Studio version 1.17 or higher.
*5. Supported only by the Sysmac Studio version 1.08 or higher.
*6. Supported only by the Sysmac Studio version 1.10 or higher.
*7. Supported only by the Sysmac Studio version 1.15 or higher.
Refer to the SYSMAC-SE[][][] Datasheet for function specifications of the Safety Control Unit.

Version Information

• Relationship between Unit Versions and Sysmac Studio Versions

EtherCAT Slave Terminal and EtherNet/IP Slave Terminal

• This configuration is used to connect the Safety Control Unit to the EtherCAT Coupler Units, and the EtherCAT Slave
   Terminal to the built-in EtherCAT master of the CPU Unit via EtherCAT.
• This configuration is used to connect the Safety Control Units to the EtherNet/IP Coupler Units.

NX Unit Corresponding version *1
Model number Unit version EtherCAT
Coupler Unit
CPU Units *2
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 --- ---

*1 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
     Refer to the user’s manuals for the specific Units for the relation between models and versions.
*2 These Units cannot be mounted to Machine Automation Controllers with NX1P CPU Units. Mount and use an EtherCAT
     Coupler Unit instead.

CPU Rack

• This configuration is used to connect the Safety Control Units to the CPU Units.

Safety Control Unit model and version NX bus master: CPU Unit
Model Unit version NX102 CPU Units Sysmac Studio
NX-SL3300 Ver. 1.0 Ver. 1.30 Ver. 1.22
Ver. 1.1
NX-SL3500 Ver. 1.0
Ver. 1.1
NX-SL5500 Ver. 1.3 Ver. 1.31 Ver. 1.24
NX-SL5700 Ver. 1.2 --- ---
Ver. 1.3 Ver. 1.31 Ver. 1.24