Using OPC UA in IIoT solutions
Data exchange between traditional automation systems and cloud-based services often raises concerns about interoperability and security. OPC UA offers secure features that help address these concerns effectively.
In brief
- OPC (Open Platform Communications) has long been a standard in industrial applications, offering a simple and quick implementation, but with certain limitations in scalability and flexibility.
- OPC UA (Unified Architecture) was developed as a significant improvement, enabling secure and standardized communication between automated processes and IT systems across different platforms.
- Its architecture supports greater scalability, interoperability, and advanced security features, making it well-suited for modern industrial environments.
- For IIoT applications, OPC UA provides many benefits thanks to the increased interoperability.
What is OPC UA?
Released in 2008, the OPC UA protocol became one of the primary standards for ensuring interoperability between digital systems. This solution aligns fully with concepts such as IIoT.
A key advantage is that OPC UA is fully compatible with OPC Classic and its functions. However, while OPC Classic operates only on Windows systems, OPC UA supports multiple platforms, including Apple, Android, Linux, and Windows, offering significantly broader compatibility.
Both OPC Classic and UA share several core functions, such as local and network server discovery, hierarchical data representation, and controlled read/write operations based on access permissions. Additionally, OPC UA is compatible with a wide range of hardware, including traditional computers, programmable logic controllers, microcontrollers, and cloud-based servers.
Message formatting and security in OPC UA
Message exchange in OPC UA occurs at both the device level and higher system levels, using two primary formats: Binary UA and XML. These formats define how messages are encoded and decoded.
Binary UA is most commonly used at the equipment level because it requires less processing power and offers higher performance. It was designed for efficient encoding and decoding, with careful consideration of data size to optimize speed.
XML, on the other hand, is employed for high-level information exchange. Clients using the OPC UA protocol can interpret XML-based messages, which provide robust capabilities for serialization and deserialization, making XML more powerful for complex data handling.
Regarding security, OPC Classic relies on Microsoft’s COM and DCOM protocols. OPC UA introduces its own comprehensive security framework, incorporating Public Key Infrastructure (PKI) and industry-standard x.509 certificates. It also supports authentication, encryption, authorization, and other advanced security measures to ensure data integrity and confidentiality.
Protocol communication
OPC UA uses two transport protocols to define communication between the client and the server: OPC TCP and SOAP/HTTP(s). OPC TCP is a dedicated protocol, meaning only OPC UA clients can interpret the transmitted information. Communication is bidirectional between client and server and is securely packaged in a binary structure.
Messages transmitted via SOAP use HTTP(s). Unlike OPC TCP, this approach offers broader possibilities for data interpretation and can even be accessed through a standard web browser. This method is widely adopted in industrial environments.
OPC UA advantages and uses in IIoT
The OPC UA protocol enables interoperability across platforms while ensuring security and scalability. It is widely regarded as a key standard for achieving IIoT system integration.
Communication through OPC UA is transparent, significantly reducing integration challenges between different manufacturers. As a result, manufacturers are increasingly required to make all relevant information available using this protocol.
Netilion ecosystem - IIoT architecture
OPC UA provides a clear and efficient method for integrating data from field equipment into higher-level systems. While MQTT (Message Queuing Telemetry Transport) is also commonly used for direct device connectivity, OPC UA remains a cornerstone for structured and secure data exchange in industrial environments.
OPC UA with JavaScript, JSON, and REST APIs
One of the key challenges in IIoT is utilizing collected data for analytics to generate actionable insights. The OPC Foundation has demonstrated examples of applying OPC UA with APIs, and similar approaches can be implemented using IIoT services such as Netilion.
Netilion Connect is an API-based connectivity service that includes an OPC server add-on, making integration with OPC UA clients straightforward. Through an OPC UA server, data can be seamlessly integrated into other solutions, such as MES or SCADA.
Using an OPC UA server as a connectivity layer for client applications offers several advantages. It requires no local installation, reducing initial infrastructure costs and ongoing maintenance efforts. All that is needed is an internet connection, making deployment fast and cost-effective.
Data collection typically relies on JSON for programming and JavaScript for implementation. As IT and automation continue to converge, programming languages will become increasingly common in industrial environments.
