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New BACnet Standard Published

March 26, 2013
ASHRAE recently announced the publication of ANSI/ASHRAE Standard 135-2012, BACnet – A Data Communication Protocol for Building Automation and Control Networks.

ASHRAE recently announced the publication of ANSI/ASHRAE Standard 135-2012, BACnet – A Data Communication Protocol for Building Automation and Control Networks.

The standard was published ahead of schedule because of wide-reaching changes in alarming functionality in Standard 135-2010 Addendum af.

Addendum af provides significant improvements in alarm handling, including fault handling, temporary alarm-recipient subscriptions, and alarm distribution, Carl Neilson, chair of the Standard 135 committee, said.

“For building owners/integrators, these changes allow improvements in interoperability between lighting-control products and other building-automation systems,” Neilson said. “Hopefully, this facilitates more deployment and integration of smart lighting controls, such as lights that turn on/off when occupants enter/leave rooms, lights that come on based on the same schedules as climate control, and opportunities to reduce lighting based on energy usage during demand/response events. With the changes in alarming, we also hope to see alarming support in ‘smaller’ devices, which should provide more alarm and fault detection with a lower engineering cost.”

Addendum af:

• Removes annexes C and D.

• Clarifies optionality of properties related to intrinsic-event and change-of-value reporting; priority_array and relinquish_default; segmentation-related properties; virtual-terminal-related properties; time-synchronization-interval, backup, and restore properties; active_COV_subscriptions property; slave-proxy properties; restart-related properties; log_deviceobjectproperty; clock-aligning properties; and occupancy-counting properties.

• Ensures that pulse_rate and limit_monitoring_interval are always together and that event notifications are not ignored because of character-set issues.

• Adds the ability to configure event-message text, dynamically suppress event detection, specify a different time delay for to-normal transitions, inhibit the evaluation of fault conditions, and send only fault notifications for some objects types; notification-forwarder and alert-enrollment object types; and an event-detection enable/disable property.

• Separates the detection of fault conditions from intrinsic reporting.

• Makes event-reporting-property descriptions consistent.

• Identifies the property in each object that is monitored by intrinsic reporting.

• Changes the reliability-property description.

• Improves fault detection in event-enrollment objects and the specification of event reporting.

• Reduces notification-server requirements.

Standard 135-2012 also includes support for lighting control through a lighting-output object, the channel object, and the WriteGroup service.

The cost of Standard 135-2012 is $140 for ASHRAE members and $170 for non-members. Copies can be ordered by phone at 1-800-527-4723 (United States and Canada) or 404-636-8400, by fax at 678-539-2129, or online at