Web Services in Building Automation: Mapping KNX to oBIX

Web services are a key technology for enabling interoperable machine-to-machine interaction over a network. They also lend themselves excellently to the integration of automation and IT systems. This paper discusses oBIX, a new standard for representing and accessing building automation (BA) data via Web services. It is shown how access to a BA system that follows the KNX protocol standard can be faithfully represented by way of oBIX entities. A prototype implementation of such a gateway is presented. The extensible nature of the oBIX data model is leveraged by using it to express the required KNX-oBIX mapping information as well. This approach allows a particularly clear and efficient gateway design.