Next Generation SCADA for Building Automation

NETxAutomation started to implement their next generation SCADA server for building automation systems called NETxLAB® Voyager Global Visualization. The NETxLAB® Voyager Global Visualization enables the control and visualization of your building automation projects. The system consists of a central server system NETxLAB® Voyager Server and the different NETxLAB® Voyager Clients. This product line enables, through its flexible number of client connections, to realize variable project sizes - from a small home to the largest projects in the world. The individual visualizations are connected as clients to the server, which is responsible for the administration. The solution provides an integrated web server that enables a global, platform independent access to the clients. To increase the data redundancy and reliability, the NETxLAB® Voyager Server can be realized as a Main/Backup solution. Even a cluster configuration of individual, networked servers is possible.

In addition to the implementation of an OPC UA interface, the main feature of this server will be a generic information model mapping device information typically found in modern home and building automation systems. A design document that shows the internal structure of their next generation SCADA server can be found here. For more information visit the the website of NETxAutomation.

Information Modelling in Building Automation

A key factor for providing interoperability is information modeling. Therefore, the different ways of information modeling that are supported by the available Web Service technologies have been investigated. In addition to the modeling concepts of OPC UA, information modeling within oBIX and BACnet/WS was examined. After this analysis phase, OPC UA information models for dedicated building automation technologies (i.e., KNX and BACnet) have been specified. The first results regarding information modeling were presented at the KNX Scientific Conference 2010. "KNX and OPC UA" presents a general introduction to OPC UA and presents an approach to model KNX installations with OPC UA. The second paper entitled "Mapping KNX to BACnet/Web" consists of a general introduction to BACnet/WS as well as an approach how BACnet/WS can be mapped to KNX.

During the specification of these models, the consortium concluded that the overall goal is not only providing models for dedicated technologies but also defining a generic information model for all kinds of building automation technologies. This generic model will be an important target within the second project year.

Web Service technologies

In addition to OPC UA, other promising Web Service technologies exist. In the field of home and building automation, candidates for Web Service technologies are BACnet/Web Services (BACnet/WS) and oBIX. Due to the importance of these promising Web Service technologies, an in-depth description of BACnet/WS and oBIX with a comparison to OPC UA has been performed. The results of the analysis of BACnet/WS and oBIX were published as two bachelor thesis ("Web Services in Building Automation with focus on BACnet/WS" and "Web Services in der Gebäudeautomation mit Schwerpunkt auf oBIX (in German only)"). Additionally, a paper that deals with BACnet/WS were presented at the KNX Scientific Conference in November 2010.

Since OPC UA is the chosen key technology within this project, a comprehensive analysis of the OPC UA specification was also done. Several white papers were prepared throughout the master course “Distributed Automation (in German only)" at the Vienna University of Technology (supervised by W. Kastner and W. Granzer). In addition to a profound description of the overall specification, a detailed investigation of available software and tool support was performed. This concerns available OPC UA Software Development Kits (SDKs) as well as OPC UA interface implementations and ways to include them into available software frameworks.

Technology survey

It is assumed that complaints about documentation and complexity of OPC UA originate mainly from the conflict between the wide range of features and possibilities of the standard on one hand and the restricted business needs of SMEs on the other. Hence, major goals of a realized survey were to identify which parts of the standard are most frequently applied and which specific sets of profiles add most value for SMEs. The survey was based on the assumption that respondents have no detailed knowledge of OPC UA profiles. Therefore, rather than using checklists, a questionnaire that allowed drawing conclusions about underlying profiles was compiled. To address a representative number and kind of stakeholders, the survey was distributed to both OPC Foundation members as well as companies that figure on the Foundation’s regular mailing list. As a result, a total of 719 responses was collected and analyzed. The results of this survey can be found here.