Permanently strong and steady wind guaranties 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, build 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 guaranty most effective operation at all times. Depending on weather condition accessibility might be infrequently, therefore all components must be construed for long maintenance intervals and of course this includes the software components. The need for long term operation leads to high requirements in terms of reliability and robustness.

Essentials for choosing OPC UA

AREVA Multibrid GmbH equipped their M5000 - a 5MW offshore wind mill - with Beckhoff CX1020 Embedded PC running on 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 onshore control room. Considering different possibilities for software communication the favored technology was OPC UA. Compared to other open standards the inbuilt security and authentication mechanism of OPC UA was the determining factor for this decision.
In a complex networking infrastructure including different subnets and domains, connected through routers and protected by firewalls, configuration and administration becomes a difficult and time-consuming task. Multiple use cases and scenarios of operation were elaborated to find sustainable solution. In the past VPN tunnel for secure transmission and remote desktop connections were used, but OPC UA includes encrypted transmission and 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 hard- or software and no extra configuration required. The risk of additional sources of failure was eliminated.

“Our CX-Embedded controller series is based on international standards: Intel embedded CPU’s, Microsoft Embedded CE/XPE OS hosting the PLC logic standard IEC6-1131-3 and also motion control” says Stefan Hoppe, Product Manager TwinCAT, Beckhoff. “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 an UA based Solution

Measurement, monitoring, and control applications must been enabled for OPC UA. Multibrid’s existing SCADA software was enhanced with OPC UA Client capabilities. In a first step Data Access functionality was implemented based on Unified Automation’s UA Client SDK. Compared to toolkit level software the Software Development Kit preserves the entire flexibility, but offers simplified class framework encapsulating 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 simply using a comfortable API for communication. The SDKs of 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, Multibrid “The UA SDK from Unified Automation made this a straightforward task.”

Successful Result

The wind turbine was enabled 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 OPC-UA industry standard delivered important business and technical benefits, 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 a minimum configuration and implementation effort. But using the open standard revealed additional benefits. Even though in a first step only Data Access functionality of OPC UA is used, 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 and it shows the confidence in OPC UA technology.

For more information about UA enabled embedded controllers from Beckhoff Automation, visit www.beckhoff.com

For more information about integrating OPC UA into your application and other solutions from Unified Automation GmbH, visit www.unifiedautomation.com