ACHRNEWS

Addendum May Lower Cost

March 3, 2008

ATLANTA - Advances related to the BACnet standard, including recommending public review for an addendum that would tunnel BACnet over ZigBee wireless networks, were made during the American Society of Heating, Refrigerating and Air-Conditioning Engineers’ (ASHRAE’s) recent Winter Meeting.

Proposed addendum q would lead to a significant reduction in the cost of installation at the sensor and controller level by reducing the amount of wired networking required in a building automation system, according to Jerry Martocci, convener of the BACnet committee’s Wireless Networking working group.

“Marrying these two technologies seemed obvious,” said Martocci. “BACnet already had the object and services model designed specifically for building automation but no wireless network, and ZigBee had the wireless capabilities but no object model for building automation. We just had to put the two together to benefit from the synergies.”

According to ASHRAE, battery-operated devices, including sensors, will most likely be ZigBee only, but powered controllers will have BACnet/ZigBee capability. Martocci noted that the “mesh” networking among ZigBee nodes leads to self-healing networks, so that even if a link between two nodes is obstructed, the “mesh” network can route around the obstructed link, leading to reliable networks.

In other developments, the BACnet committee worked toward approval of nine additional addenda during the meeting. “Only a few of these are going out for first public review,” said BACnet chairman Bill Swan. “But it is our expectation that these are all likely to pass without significant comments.”

One such addendum, Addendum j, provides support for physical access control. This was drafted by the Life Safety and Security working group, comprised of BACnet and experts from the physical security industries.

For more information, visit www.ashrae.org.

Publication date: 03/03/2008