OPC UA Protocol Converters

The industrial landscape is rapidly evolving with the widespread adoption of Industry 4.0, Industrial IoT (IIoT), and smart manufacturing. These transformations demand seamless interoperability between a wide range of machines, devices, and systems — many of which were never designed to communicate with one another. One major enabler of this cross-system communication is the OPC UA protocol converters.

While OPC UA Protocol Converters has established itself as the premier standard for secure and platform-independent industrial communication, the reality is that thousands of devices in factories and plants still operate on legacy or proprietary protocols such as Modbus, Profinet, BACnet, CANopen, and OPC Classic (DA/AE/HDA).This is where OPC UA protocol converters come into play: these gateways act as translators, enabling communication between modern OPC UA-based systems and legacy or alternative protocols. In this article, we’ll explore what OPC UA protocol converters are, how they work, where they are used, and what to consider when deploying them.

What Is an OPC UA Protocol Converter?

An OPC UA protocol converter — often called a gateway or bridge — is a hardware device or software solution that enables bidirectional communication between OPC UA and another industrial protocol. These converters translate data structures, communication formats, and security features from one protocol to another, ensuring compatibility and data integrity.

Basic Functionality
• Protocol Translation: Converts messages from a source protocol (e.g., Modbus TCP) into OPC UA and vice versa.
• Data Mapping: Maps tags or data points between systems.
• Security Bridging: Wraps insecure protocols within OPC UA’s secure framework.
• Interoperability Layer: Allows devices from different manufacturers and generations to work together

⁠Why Use an OPC UA Protocol Converter?

Legacy Device Integration

Many industrial facilities have legacy PLCs and RTUs that communicate using outdated protocols. Replacing them entirely can be costly and risky. Protocol converters enable these devices to participate in modern OPC UA-based ecosystems without replacement.

Vendor Interoperability

Different OEMs often use proprietary or semi-standard protocols. OPC UA gateways allow integration of systems from Siemens, Schneider Electric, Rockwell, Mitsubishi, and more under a single OPC UA umbrella.

Edge-to-Cloud Communication

OPC UA’s rich information modeling and security make it ideal for sending contextualized data to the cloud. Gateways allow MQTT, HTTP/REST, or AMQP integration with services like Azure, AWS, or Google Cloud.

Industrial Data Normalization

Protocol converters also serve as data normalization engines, ensuring that data from disparate sources conforms to common semantic models and taxonomies

Common Protocols Connected via OPC UA Converters

Protocol
Description
Use Case
Modbus (RTU/TCP)
Simple, widely used field protocol
Connecting sensors, legacy PLCs
Profinet
Siemens’ real-time industrial Ethernet
Integrating with OPC UA MES/SCADA
EtherNet/IP
Rockwell’s Ethernet-based protocol
Interfacing ControlLogix/CompactLogix with OPC UA
BACnet
Building automation systems
HVAC, lighting systems integration
OPC DA/AE/HDA
Older OPC Classic interfaces (COM/DCOM)
Migrating to OPC UA from legacy OPC applications
CANopen
Low-level fieldbus used in motion control
Converting data from drives and servo systems
DNP3
Used in electric utilities
Substation automation and grid integration

How OPC UA Converters Work: Architecture Overview

Hardware-Based Gateways

These are physical devices (DIN-rail mountable, industrial grade) installed near field equipment or control panels.
• Multiple Ethernet or serial ports
• Protocol stacks embedded in firmware
• Configuration via web interface or engineering tool
• Supports rugged environments (wide temp range, DIN mount)

Examples:
• HMS Anybus gateways
• Softing uaGate
• Advantech industrial converters

Software-Based Converters

These run on industrial PCs, edge devices, or cloud VMs.
• Flexible deployment (Linux, Windows, containers)
• Supports virtual environments
• Can scale horizontally
• Customizable with SDKs (e.g., open62541, Eclipse Milo)

Examples:
• Kepware KEPServerEX
• Matrikon Flex OPC UA SDK
• Prosys OPC UA SDK Server

Data Mapping & Transformation

Converters include tools for mapping:
• Tags (address → variable name)
• Units (e.g., °F to °C)
• Data types (e.g., INT → Double)
• Structures (flat to hierarchical OPC UA objects)

Features Why It Matters
Protocol Compatibility
Ensure it supports your source and target protocols
Bi-Directional Communication
Enables reading and writing between systems
Security Support
TLS encryption, certificate handling for OPC UA
Performance
Low latency and high throughput for real-time control
Redundancy
Failover mechanisms for mission-critical systems
Scalability
Can it handle hundreds/thousands of tags?
Ease of Configuration
Intuitive GUI, import/export mappings
Logging and Diagnostics
Essential for debugging integration issues
Cloud Connectivity
MQTT/HTTP/REST bridges for IIoT platforms

Use Cases and Applications

Smart Manufacturing

A factory with Modbus-based legacy machines uses OPC UA converters to:
• Feed real-time data to a centralized SCADA system
• Enable predictive maintenance via AI analytics
• Integrate with ERP systems using OPC UA information models

Power & Energy

Substations using DNP3, Modbus, or IEC 60870 protocols require OPC UA gateways to:
• Interface with control centers via IEC 61850/OPC UA
• Enable remote monitoring via cloud dashboards
• Ensure cybersecurity compliance (NERC CIP)

Building Automation

A building uses BACnet and KNX for HVAC and lighting. An OPC UA converter allows:
• Unified building management
• OPC UA-based dashboards and alerts
• Integration with smart grid systems

Food and Beverage

Legacy SLC 500 and MicroLogix PLCs use serial Modbus RTU. With converters, these:
• Integrate with an OPC UA SCADA system
• Enable recipe and batch data collection
• Comply with traceability regulations (e.g., FDA 21 CFR Part 11)

Challenges in Using OPC UA Protocol Converters

Data Model Limitations

Many legacy protocols are flat and lack semantic structure. Translating them into OPC UA’s object-oriented model can be complex and may require manual modeling or use of companion specifications.

Real-Time Performance

Some converters may introduce latency due to buffering or polling cycles. Real-time applications may need special tuning or use of hardware-based converters with deterministic networks.

Security Bridging

Legacy protocols lack encryption/authentication. Wrapping them in OPC UA does not make them secure — physical and network-level protections are still required.

Maintenance & Updates

Firmware or software updates are essential to maintain security. Devices must support over-the-air updates or centralized management platforms.

Best Practices for Deployment
• Start with a pilot project in a controlled environment.
• Map data carefully — consider naming standards, units, and namespaces.
• Use tags hierarchically when converting flat data models.
• Apply role-based access control on OPC UA clients and servers.
• Monitor performance and diagnostics via the converter’s tools.
• Plan for scalability: choose devices that can grow with your needs.
• Secure the network: use VPNs, firewalls, VLANs, and endpoint protection.

Standards and Future Trends

Companion Specifications

OPC UA Foundation continues developing domain-specific information models, such as:
• OPC UA for Machinery
• OPC UA for Weighing Systems
• OPC UA for Drive Technology
• These models improve plug-and-play integration between converters and applications.

OPC UA over TSN

Time-Sensitive Networking (TSN) integration will allow converters to support deterministic real-time communication.

AI and Semantic Mapping

AI-based tools may soon auto-map between legacy tags and OPC UA object models using metadata, ontologies, and historical context.

Digital Twins & Edge Intelligence

OPC UA converters will become smarter, acting not just as translators but also as edge processors that filter, aggregate, and enrich data before forwarding it to enterprise systems or digital twin platforms.

OPC UA protocol converters are the unsung heroes of modern industrial interoperability. They form the connective tissue between old and new, allowing businesses to modernize operations without replacing entire infrastructures.

From legacy PLCs and sensors to cloud-based analytics platforms, these converters unlock the full potential of OPC UA by extending its reach into every corner of the industrial ecosystem.

As the demand for seamless, secure, and smart industrial communication continues to grow, the role of protocol converters will only become more critical. Selecting the right converter — and deploying it thoughtfully — ensures you’re ready to meet the challenges and opportunities of Industry 4.0 head-on.

ANC-300e: Ethernet/IP & Modbus TCP to Serial Modbus RTU, DF1 Converter

The ANC-300e has the combined performance as an Ethernet and RS-485 serial converter. The gateway behaves like a protocol converter/translator that allows difficult data interchanges and connections between incompatible networks.  Protocols include:

RS485 serial Protocols:

Modbus RTU, Modbus Sniffer, A.O. Smith AIN, A.O. Smith PDNP, BACnet MS/TP Client, BACnet MS/TP Server, TCS Basys Master, MSA Chillgard Monitor, DMX 512-Master, DMX-512 Slave, M-Bus Master, Metasys N2 Master, Metasys N2 Slave, Siemens FLN Master, Siemens FLN Slave, Sullair Master, Toshiba ASD Master, Toshiba PLC Master, DF1.

Ethernet Protocols:

Ethernet/IP Client/Server, AB CSP Ethernet Client/Server, Modbus TCP/IP, Profinet IO, BACnet/IP BBMD, BACnet/IP Client, BACnet/IP Server, Baumer VeriSens Client, CC-Link IE SLMP Client, MELSEC Client/Server, Generic Socket Client/Server & GreenFumeHood Client, Modbus TCP.

ANC-300e is an easily configurable Ethernet / RS-485 converter gateway, that provides integrated communication between all the above common industrial and commercial communication networks. As part of the ANC Gateway Converter Series, the ANC-300e provides a common platform which is convenient and easy to setup in all products.

The Automation Network ANC-300e Ethernet & Fieldbus Gateway Converter allows data to be seamlessly transferred between Ethernet to Ethernet and Ethernet to RS-485 networks with simple configuration.

Coming Soon: Need to get data from your EtherNet/IP or Modbus TCP/IP-based devices to your OPC UA clients? This ANC-300e additional functionality is coming shortly.

Data Highway Plus to Ethernet (S02)

In today’s episode of The Automation Show, I unbox and setup an ANC-100e  Data Highway Plus (DH+) to Ethernet Converter Data Highway Plus to Ethernet bridge from Automation Networks. For more information about the show (and how you could win an ANC-100E) check out the “Show Notes” located below the video. The Automation Show, Episode 2 Show Notes: NOTE: Would you like your … Continue readingData Highway Plus to Ethernet (S02)

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