Unified Automation’s Software Development Kit (SDK) was the favored technology to integrate OPC UA in Alpha Ventus, an offshore wind park test site in the North Sea. OPC Unified Architecture is ensuring fast, reliable and secure communication with onshore control applications and enterprise information systems.

Permanently strong and steady wind guarantees effective wind energy generation 45 kilometers from the German coast. Each wind mill is designed as an autonomous, fully automated, self-monitoring energy plant. Offshore wind parks, built far away from the coast and waterways, have very low environmental impact. They must run under rough conditions like humidity, salt and extreme temperatures and their autonomous control system must guarantee effective operation at all times. Depending on weather conditions, accessibility may be limited, therefore all components must be constructed for long maintenance intervals and, of course, this includes the software components. The need for long term-operation leads to stringent requirements in terms of reliability and robustness.

Essentials for Choosing OPC UA

AREVA Multibrid GmbH equipped its M5000, a 5MW offshore wind mill (see photo), with a Beckhoff CX1020 Embedded PLC running on Microsoft Windows CE. Even though the fully automated wind turbine has self-controlling capabilities, operators need a way to constantly monitor plant and equipment conditions remotely from the onshore control room. After considering different possibilities for software communication, the favored technology was OPC UA. Compared to other open standards, the built-in security and authentication mechanism of OPC UA were the determining factors for this decision.

Configuration and administration becomes a difficult and time-consuming task in a complex networking infrastructure that includes different subnets and domains, connected through routers and protected by firewalls. Multiple use cases and scenarios of operation were explored to find a sustainable solution. Using VPN tunnel for secure transmission and remote desktop connections would be one possible solution, but OPC UA adds user authentication and audit functionality down to individual data points. The OPC UA communication is directly integrated into the embedded PLC. There is no accessory hardware or software and no extra configuration required, minimizing the risk of additional sources of failure.

“Our CX-Embedded controller series is based on international standards: Intel embedded CPUs, Microsoft Embedded CE/XPE OS hosting the standard IEC6-1131-3 PLC logic and also motion control,” says Stefan Hoppe, Product Manager for TwinCAT at Beckhoff Automation. “For connectivity we provide OPC UA server functionality directly integrated into our industrial controller. Important for customers is the easy handling of connectivity: Our UA server does not require configuration but guarantees data consistency with the PLC.”

Realization of a UA-based Solution

Measurement, monitoring and control applications must be enabled for OPC UA. Multibrid’s existing SCADA software was enhanced with OPC UA Client capabilities. As a first step, OPC Data Access functionality was implemented based on Unified Automation’s UA Client SDK. Compared to toolkit level software, the Software Development Kit preserves flexibility while offering simplified class framework that encapsulates common reusable functions. The full-featured UA SDK library completely hides the message handling and security, including all transport related tasks. The application developer can concentrate on the higher level logic by simply using a compatible API for communication. The SDKs from Unified Automation are utilized in many OPC UA products and reflect all the experience of the first professional supplier of platform independent UA development frameworks.

“The integration of OPC UA Client functionality into our SCADA software was an important step towards OPC UA technology,” says Bernd Zickert, head of development for Multibrid. “The UA SDK from Unified Automation made this a straightforward task.”

Successful Result

The wind turbine was able to communicate with enterprise information systems onshore for remote control, maintenance, and measurement. Adding further UA functionality like Alarms and Conditions, Historical Access and Methods now gives the option of seamless enhancements in the future. The fast and secured communication between industrial automation and the enterprise systems that support the OPC UA industry standard deliver important business and technical benefits, including reduced administration combined with high reliability.

Switching to the new OPC UA technology has solved today’s security problems when accessing plant information. In a complex network environment, secure and reliable communication was established with minimum configuration and implementation effort. But using the open standard revealed additional benefits. Deploying the Data Access functionality of OPC UA is just a first step; new opportunities arise from the rich capabilities that are built into the core of Unified Architecture. These will emerge in future versions of Multibrid’s SCADA software, which shows the confidence in OPC UA technology.

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