The Reynolds Company
Company Logo

OPC UA Connectivity to Rockwell Automation® Controllers

Wayne Welk11/10/2022

OPC United Architecture (UA) continues to be a preferred method to interconnect industrial control systems securely and reliably for Industry 4.0 and Industrial Internet of Things (IIoT) initiatives. OPC UA is the latest OPC standard created for industrial applications by the OPC Foundation, and combines their existing standards, such as OPC DA, OPC A&E, and OPC HDA, into a Service Oriented Architecture (SOA) which is platform independent.

OPC UA combines two mechanisms to implement data exchange:

  • A client-server model, in which OPC UA clients use the dedicated services of the OPC UA server. This peer-to-peer approach provides a secure and confirmed exchange of information, but with limitations regarding the number of connections.
  • A publisher-subscriber model where an OPC UA server makes configurable subsets of information available to any number of subscribers. This kind of broadcasting mechanism provides an unconfirmed “fire and forget”-style exchange of information.

Three types of OPC UA solutions will be discussed:

  • In-Chassis Gateway – installed directly in a ControlLogix chassis
  • Industrial Hardware Gateway – a standalone industrial gateway that DIN rail mount
  • Software Gateway – software-based OPC UA servers that require a PC to operate

Rockwell Automation and their Technology Partners offer various solutions for OPC UA connectivity.

In-Chassis Hardware Gateway

Softing eATM OPC UA Server Module for ControlLogix

The Softing in-chassis OPC UA server module for the ControlLogix platform acts as a transaction server to eliminate the need for additional PC and software applications to connect to OPC UA clients.

 The eATM OPC UA server supports OPC UA and EtherNet/IP protocols, offers two independent 10M/100M/1G Ethernet ports, and can integrate with additional ControlLogix and CompactLogix controllers on the network.

The eATM can access the local controller’s data using native backplane communication resulting in an increased transaction speed of up to 1000 tags/second.

Industrial Hardware Gateways

ProSoft Technology EtherNet/IP to Modbus TCP/IP to OPC UA Server

The ProSoft Technology, PLX32-EIP-MBTCP-UA, EtherNet/IP to Modbus TCP/IP to OPC UA server communication gateway allows high-speed tri-directional data transfers between EtherNet/IP PACs and Modbus TCP/IP devices, while also providing an OPC UA Server connection. 

The Modbus TCP/IP driver features multiple, simultaneous client and server connections for faster data transmission. An EDS AOP is provided for easy integration into the Logix controllers using EtherNet/IP.

The OPC UA Server supports 10 simultaneous OPC UA sessions that provide access to EtherNet/IP and Modbus TCP/IP data from the respective networks.

Anybus Edge Gateway EtherNet/IP

The Anybus family of Edge Gateways enable edge intelligence, intelligent decentralized operations to be executed close to the data sources.

The ABE04020 model supports EtherNet/IP, Modbus-TCP client/server, Modbus-RTU master/slave, OPC UA, MQTT, SNMP and SNTP communications, as well as connectivity to the HMS Hub.

eWon Flexy 205

The eWon Flexy 205 is a unique solution for OPC UA for several reasons.  Unlike most other industrial OPC UA gateways, the Flexy 205 can act as both an OPC UA server and client.  Flexy data services also include PLC data acquisition, alarm management and notification, data logging and retrieval, local web dashboards, remote access, and programming (Basic and Java).

Data publishing protocols include OPC UA, MQTT, Modbus, SNMP. HTTPS.

Software Gateways

FactoryTalk® Linx Gateway

The FactoryTalk® Linx Gateway provides a Classic OPC-DA and OPC UA server interface to deliver information collected by FactoryTalk Linx from Logix 5000™ and other Allen‑Bradley controllers to external OPC clients.

The benefits of using FactoryTalk Linx Gateway have optimized communications with the Logix5000 family of controllers, as well as the ability to communicate with legacy Allen‑Bradley PLC-5® and SLC™ 500 controllers.

FactoryTalk® Edge Gateway™

FactoryTalk Edge Gateway software unifies data from industrial sources and control or automation systems. It integrates with various cloud, IIoT and big data applications including ThingWorx, Microsoft Azure IoT Hub, Microsoft SQL, MQTT, InfluxDB and more.

FactoryTalk Edge Gateway will support OPC UA for data ingress in the upcoming 1.4 release.


When faced with multi-vendor control systems in your facility, KEPServerEX can connect disparate devices and applications from the plant floor to enterprise information systems.  KEPServerEX can act as a single source of industrial automation data for all your applications and provides critical technical features that enable accessibility, aggregation, optimization, connectivity, security, and diagnostics.

Want to learn more?

Contact your local specialist from The Reynolds Company to learn more about connectivity solutions for OPC UA with Rockwell Automation and their Technology Partners.

Additional Resources

Written By


Automation Specialist | Louisiana