OMRON NJ/NX OPC UA Configuration Guide

OMRON NJ/NX Series Controller OPC UA Server Implementation and Security Configuration Complete Guide

In modern industrial automation systems, breaking down the data barriers between the control layer and IT systems (such as MES, SCADA) is the key to achieving intelligent manufacturing. OPC UA (Open Platform Communication Unified Architecture), as a platform independent, secure and reliable communication protocol, has become the core standard of Industry 4.0. Omron has integrated OPC UA server functionality into its NJ/NX series Machine Automation Controller, allowing the upper system to directly and securely access variable data within the controller through standard Ethernet without the need for intermediate conversion computers. This article aims to provide engineers with a detailed technical guide on configuring, optimizing, and maintaining OPC UA servers on NJ/NX series controllers.

System Overview and Applicable Hardware

The OPC UA server function enables NJ/NX series CPU units to act as OPC UA servers, accepting connection requests from SCADA or other OPC UA clients, and enabling read and write operations on global variables and function block instances within the controller. This feature is deeply integrated with the built-in EtherNet/IP port (specific port) of the controller.

Supported CPU models:

Not all CPUs support this feature, please confirm the hardware version before use:

NX701-1 □□□: Unit version 1.24 or higher.

NX502-1 □□□: Unit version 1.60 or higher.

NJ501-1 □□□: Unit version 1.17 or higher.

NX102- □□□□: Unit version 1.30 or higher.

Key specification limitations:

Connection port: limited to the built-in EtherNet/IP port of the CPU unit (specifically PORT 1 for NX701/NX502/NX102).

Maximum number of sessions: The server can support up to 5 OPC UA client sessions simultaneously.

Monitoring items: The entire server supports up to 2000 monitoring items (up to 20000 for specific models and higher versions).

Number of variables to be published: Up to 10000 network variables can be published (the higher version NX701 supports 100000).

Detailed configuration steps: from beginner to proficient

The configuration of the NJ/NX OPC UA server is mainly divided into four stages: network layer settings, security settings, variable publishing, and online operations, all of which are carried out in Omron's Sysmac Studio software environment.

2.1 Basic Network Settings: Determination of IP Address

OPC UA communication relies on a stable IP address.

Navigate to Configuration and Settings ->Controller Settings ->Built in EtherNet/IP Port Settings.

In TCP/IP settings, select "Fixed settings" or "IP address obtained from BOOTP server".

Important warning: It is strongly not recommended to use DHCP (Dynamic Host Configuration Protocol). The server certificate is bound based on the IP address at the time of generation. If there is a subsequent change in IP address, it will result in a mismatch between the server certificate and IP, causing client connection failure and triggering the 'Server Certificate Mismatch' event.

2.2 OPC UA Server Core Settings

Enable service:

In the multi view browser of Sysmac Studio, find Configuration and Settings ->OPC UA Settings ->OPC UA Server Settings.

Change the 'Server Function Settings' from' Do Not Use 'to' Use '.

Key step: After downloading this project to the controller, it is necessary to cycle the controller to power off and then power on or perform a "controller reset" before the OPC UA server can start.

Endpoint and Port Configuration:

The 'Endpoint' field will automatically display the server's URL in the format of opc.tcp://[IP address]: [port number]/. The default IP is 192.168.250.1 and the default port is 4840.

The 'port number' can be customized (range 1025 to 65535), but it is necessary to ensure that the port is not occupied by other services such as FTP, HTTP, etc.

Execution log settings:

To trace the operational status, connection requests, and errors of OPC UA servers, it is strongly recommended to enable execution logs.

Set 'Record Execution Log' to 'Record'.

The number of configurable files (2-100) and the number of records per file (100 to 65536). The log files are saved on the SD memory card of the CPU unit.

2.3 Variable Release: Building Address Space

OPC UA clients need to access controller data through address space. Engineers need to specify which variables are visible to the outside world.

Global variable release:

In the global variable editor, find the variable that needs to be published.

Set its' Network Publishing 'attribute to' Publish Only ',' Input ', or' Output '. System defined variables cannot be published.

User defined feature block variable release (supported in higher versions):

You can select a specific namespace or feature block instance for publishing in the "Network Publishing Settings" of the "OPC UA Server Settings".

This allows structured control logic (such as motor control blocks) to be directly exposed to the upper system.

Expansion control of structures and arrays: