BACnet/XML Working Group Recommends Review of BACnet Web Services Addendum
BACnet Web Services Initiative Goes to Public Review
Nashville, TN, USA.
After months of intense effort by the Web Services Task Team of the BACnet/XML Working Group, SSPC 135 has unanimously voted to recommend public review of an addendum to BACnet-2004 that specifies the use of "web services" to provide a means to integrate building automation and control systems with other enterprise computing applications. Web services provide for computer-to-computer applications many of the same advantages that the World Wide Web provides for human-to-computer information access. Potential uses of the technology include simplifying access to building energy and performance data for inclusion in spreadsheets and other management reports; accessing equipment run-time data for use by maintenance management systems; allowing tenant access to, and control of, space temperature setpoints; coupling of room scheduling with ventilation and comfort control; and many more.
The new addendum is in two parts. The first proposes an Annex N to BACnet that defines the BACnet Web Services interface, BACnet/WS. This interface is intended to be "protocol neutral" in that the defined web services can be used with any underlying protocol including BACnet, Konnex, MODBUS, LON or legacy proprietary protocols. This has been accomplished by defining an application program interface (API) to read and write the common elements of all building automation and control systems such as values, schedules, trend logs, and alarm information using services such as 'getValue' and 'setValue' that use a simple "path" to define the intended data source. An example of such a path would be: "/ABC HQ/Conference Room A/Space Temperature". The proposed standard also provides powerful mechanisms for "localization" where certain types of data such as time, date and numbers can be formatted according to local custom and language. Text names and descriptions may also be accessed according to the local language. Several manufacturers have already indicated their intention to display Annex N gateway products at the AHR show in January in Orlando.
The second part of the addendum contains an addition to BACnet's Annex H, Combining BACnet Networks with Non-BACnet Networks, that prescribes the gateway mapping specifically to and from BACnet messages.
The combined effect of the BACnet/WS annexes is to provide a set of generic web services that can potentially interface to any building automation protocol as well as to describe exactly how this interface would work with underlying BACnet systems.
Prepared by Robin Cover for The XML Cover Pages archive. See details in the news story "ASHRAE Releases BACnet Web Services Interface Specification for Public Review." General references in "XML and Web Services for Facilities Automation Systems."