Network communication via TwinCAT OPC UA

Platform-independent and secure data exchange

Beckhoff implements the new OPC UA specification in its PC-based controllers. OPC is an established and recognised standard for data exchange between control and HMI in manufacturing and process automation. The new "Unified Architecture" specification creates the basis for a platform-independent communication and information technology. UA offers scalability, network capability, platform independence and security. Therefore, it can be used in a wide range of applications, including the control, MES and ERP layer. At the Hannover Fair in the "Application Park" Beckhoff will demonstrate the potential of OPC UA based on production technology and robotics applications.

As an early OPC UA adopter Beckhoff had already successfully tested its products by the end of 2007, resulting in the TwinCAT OPC UA server and client for Windows XP and CE. The existing OPC technology was based on the Microsoft COM/DCOM model and was therefore limited to Microsoft-based operating systems. The new OPC UA standard is based on TCP communication and is therefore platform-independent. Integrated UA data encryption based on international security standards guarantees secure communication between client and server. The TwinCAT OPC UA components are ideally suited for large and small control platforms such as the Beckhoff Embedded PCs from the CX series running under Windows CE.

The application of TwinCAT OPC UA servers is straightforward, since OPC requires almost no network configuration: Direct UA-TCP communication is available as soon as a PLC is available in the network.

The UA server detects the variables identified for UA access in the PLC program and makes them available in the network. In addition to standardised exchange of PLC process data, the UA solution from Beckhoff now also offers device-specific information and services. Parameters that can be read include hardware information such as platform and fan speed as well as software information such as the operating system version, the MAC-ID, available memory and screen resolution. The Beckhoff UA client supports communication with other UA servers such as controllers from other manufacturers, which are directly integrated in the data exchange with TwinCAT. Data exchange between the office/service level is routed via several transport gateways right down to the machine level.

OPC UA applications at Hanover Fair

In the Application Park Beckhoff and its partners demonstrated the new OPC UA technology based on selected production and manufacturing control and robotics application examples. The Fraunhofer Institute for Manufacturing Engineering and Automation (IPA) recognised the potential of the new UA standard at an early stage and extended the control system of the mobile robot Secur-o-bot for communication with OPC UA. IPA project manager Matthias Bengel said: “OPC UA offers a highperformance transport layer based on international standards. UA communication features integrated security consisting of authentication and encryption and is ideally suited for safe and flexible communication with mobile robots.” The standardised communication protocol makes integration into larger systems straightforward, and the robot can realise higher-level functions such as automatic patrol, sampling of sensor data, automatic alarm messages or remote query of individual sensor values safely and in real-time. The mobile robot is controlled by a Beckhoff Industrial PC C6920 with Windows XP Embedded. Using TwinCAT I/O it was easy to integrate the existing IPA control software with the real-time capable EtherCAT fieldbus.