ASHRAE Journal - November 2010 - B24

into tables, performing error-checking and reporting errors, and performs and reports results of calculations. BIG-EU provides a manual for properly using the B-PAT file called the “B-PAT Description.” This manual provides necessary definitions, BACnet addressing rules, special requirements for BACnet/IP networks, the use of the B-PAT in a project from planning through implementation and subsequent revisions, and is followed by detailed information on use of the various worksheets in the B-PAT file. In addition, several years ago BIG-EU published an aid to consultants specifying BACnet’s alarm systems, in the form of a white paper on BACnet’s two systems of detecting and issuing alarms. The white paper, “Compare Intrinsic and Algorithmic Reporting: The Project Engineer’s View,” was generated in response to a number of bid invitations that seemed to show a lack of clear understanding of BACnet alarming. Internal European efforts, such as the B-PAT, have the potential to produce results useful across the wider world of BACnet. One is the creation of WG-Germany, a working group for planners, specifiers, system integrators and consultants that addresses the particular regulatory environment in Germany. One such organization, AMEV, the “Arbeitskreis Maschinen- und Elektrotechnik staatlicher und kommunaler Verwaltungen” (Mechanical and Electrical Engineering Working Group of German National, Regional and Local Governments), has published (in German only) “BACnet in Public Buildings– BACnet 2007,” a recommended practice guide for use by governmental authorities throughout the country, currently under revision for publication this year.

Testing BACnet
One additional aid published by BIG-EU is for manufacturers of BACnet devices. “Conformance Testing and Certification— a BACnet Handbook” lays out the process for preparing and submitting devices for BACnet conformance testing, obtaining the BTL Mark for devices that pass (and rules for the use of the Mark) and achieving certification. As it notes in the introduction: “BACnet Interest Group Europe defines a certification/listing scheme for products conforming to the BACnet protocol standard. This handbook describes this scheme, the certification/ listing process and the process to qualify test labs.” Originally published in 2006, this guide is being updated to reflect procedural changes resulting from the convergence of the BIG-EU and BI testing labs towards identical testing with unified listing and certification, and will be necessary
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as additional BACnet testing labs open around the world. In addition, BIG-EU has conducted pre-testing workshops to acquaint manufacturers with the tools and processes used in BACnet testing to prepare them for the actual submissions to the test lab. The desire to converge the testing conducted by these two BACnet labs has been around for as long as there have been two such labs, but the different market forces between Europe (Germany, in particular) and North America sent the two organizations’ test-development working groups in different directions. The North American group advanced in new test drafting and deployment while BIG-EU honed in on automated test execution with automatic certification-level documentation, but both were effectively working from the same scripts. With the increasing maturity of the tests and testing tools, the convergence was able to get under way two to three years ago with expressed wishes for plans and signed agreements. The process is ongoing, but many hurdles have already been cleared, including having a single website to list products approved by either test lab (www. bacnetinternational.net/ btl/) instead of a separate site for each lab and merging the two test-development working groups into a single group. BIG-EU and BI continue to sponsor “plugfests,” which are cooperative events where manufacturers bring their BACnet devices to test with other BACnet devices. Although the test lab working groups have long defined interoperability requirements over and above the BACnet standard, the flexibility of the standard means that implementers’ assumptions need to be checked. In general, issues are most likely to be in an area once considered out of scope by the original BACnet committee: configuring devices using standard BACnet services. BIG-EU’s next plugfest is scheduled to be held in early May 2011, possibly in Vienna to attract even more North American participation. In the first BIG-EU plugfests there were observable differences between European and North American implementation philosophies, but six years later, with more companies from around the world attending both plugfests, those differences have largely vanished.

Summary
As the BACnet standard matured, it spread from its first applications in HVAC control to integrate other formerly independent areas of building automation including fire/life safety, physical access control and more. Similarly, the world of BACnet has grown from a few relatively independent regional efforts to an increasingly integrated global community.
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ASHRAE Journal - November 2010

Table of Contents for the Digital Edition of ASHRAE Journal - November 2010
