What is OPC UA? Key Concepts and Basics Explained
OPC UA is short for Open Platform Communications Unified Architecture. It refers to an interoperability standard for industrial data exchange. OPC UA was developed specifically for applications in the Industry 4.0 environment and the Internet of Things (IoT).
The original OPC standard was based on Windows DCOM and primarily designed for local use. In contrast, OPC UA is platform-independent, service-oriented, and developed for secure communication across networks.
The standard enables scalable, secure communication between a wide variety of devices and systems. It ensures uniform data formats and protocols at the interfaces of various components. At the same time, comprehensive security mechanisms protect the communication.
Benefits for Connected and Secure Industrial Communication
Platform Independence
Systems can communicate with each other in a standardized way — regardless of manufacturer, operating system, or technical environment. The platform-independent architecture enables direct machine-to-machine communication. As a result, collaboration between different systems in industrial applications is improved.
Security
The architecture uses modern security features. Data is protected through encryption, authentication, and authorization, even in open networks or the cloud.
Companies retain control over access while meeting key requirements for data protection and IT security.
Flexibility & Scalability
The Service-Oriented Architecture (SOA) of OPC UA provides the foundation for flexible and modular communication. It uses standardized interfaces for the exchange of data and services and is independent of the transport protocol.
A wide range of protocols is supported, including TCP/IP, HTTPS, MQTT, and OPC UA over TSN. This allows different devices and systems to work together seamlessly, from legacy controllers to modern IoT devices.
The structured and scalable design makes it easy to integrate new devices or OPC clients without affecting existing systems. As a result, the solution remains adaptable in the long term and helps protect investments.
Standardization
The OPC UA standard is maintained by the OPC Foundation and is recognized worldwide. It ensures standardized communication and thus provides long-term investment security.
It is complemented by Companion Specifications – extensions specifically tailored to individual industries. These are based on information modeling and enable a clear, object-oriented description of industrial data, which is a key requirement for integration into modern Industry 4.0 systems.
Flexible Communication Models for Diverse Industrial Requirements
The data transmission occurs via a classic client-server model or a publisher-subscriber (pub/sub) principle.
Both approaches are based on a service-oriented architecture (SOA). This means that the software consists of several small, specialized services that work together over a network. This enables flexible and scalable integration into modern Industry 4.0 environments.
Client-Server Model
In this model, the server acts as the data provider. OPC clients can specifically request, write, or subscribe to information, such as data changes, states, or alarms.
Communication takes place via standardized data access services. This allows different systems to access data according to uniform rules. New measurements or status changes are quickly detected and can be used immediately for queries or control tasks.
Publisher-Subscriber Model
Here, a publisher actively sends data to one or more subscribers without the need for a direct query. This model is particularly suitable for real-time applications with multiple recipients for example, in large plants or for machine-to-machine communication.
By using OPC UA over TSN, this model can also be applied to time-critical applications in production.
Flexible Integration Approaches for Different Industrial Environments
The following examples illustrate typical use cases of OPC UA communication at the interface between OT and IT.
1. Modernization of legacy systems through OPC UA integration
Many older machines still operate with proprietary interfaces or outdated protocols. To integrate them into modern IT environments, retrofit solutions are used to make existing controllers digitally accessible.
These include hardware gateways that connect controllers directly to higher-level systems via OPC UA or MQTT. Software solutions such as Softing’s dataFEED OPC Suite also integrate legacy equipment through Windows-based servers — without any modification to the machine hardware.
2. Efficient connection and integration of OPC UA servers in modern facilities
An increasing number of devices in modern plants already come with an integrated OPC UA server. Today, the main challenge lies in integrating these data sources in a simple, secure, and efficient way.
With OPC UA, machine data can be collected centrally. This data can then be transmitted to cloud platforms or analytics applications using common IT protocols such as MQTT. The result is scalable IoT architectures that simplify data exchange between production and IT systems — a key factor for greater transparency and efficiency in connected manufacturing.
3. Standardization and integration through Companion Specifications and OPC UA information models
With increasing digitalization, the need for standardized interfaces and semantic data descriptions is growing. Companion Specifications and OPC UA information models provide the foundation for consistent device and machine data.
This standardization simplifies integration into IoT platforms, for example, through Unified Name Spaces (UNS), and ensures a future-proof data architecture.
Flexible Integration Approaches for Different Industrial Environments
The integration of industrial data must fit seamlessly into a company’s existing processes as well as its IT and OT infrastructure. Standard software covers many requirements and simplifies implementation. For specific use cases, different technical approaches are available:
- Container-based software solutions – for flexible and scalable applications in modern IT architectures
- Windows-based systems – proven in traditional production and enterprise environments
- Hardware solutions with open interfaces – for direct access to machine and control data on the shop floor
These approaches enable scalable, secure, and future-proof data communication — an essential foundation for Industry 4.0, IIoT, and end-to-end automation.
Software & Hardware for OPC UA
Do you want to make your industrial data communication secure, efficient, and future-proof?
Then Softing Industrial is your ideal partner. With decades of OPC UA expertise, we provide proven software and hardware solutions for seamless and reliable integration across connected industrial environments.
Our portfolio includes:
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Software solutions for data connectivity, aggregation, and forwarding
- dataFEED OPC Suite: Windows-based OPC servers and middleware for consistent data collection and provisioning
- Secure Integration Server and edgeAggregator: Platforms for centralized data aggregation and secure management
- edgeConnectors, edgePlugs, smartLink SW-HT, smartLink SW-PN: Container-based applications for flexible and scalable integration scenarios
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Development tools
- OPC UA SDKs: Libraries for developing custom OPC UA server and client applications
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Hardware gateways
- smartLink Gateways: For parallel network access to controllers
- edgeGate, uaGates, eATM Manager Control Logix: For direct access to control data
