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BACnet™, the ASHRAE Building Automation and Control Networking Protocol

BACnet, the ASHRAE building automation and control networking protocol, has been designed specifically to meet the communication needs of building automation and control systems for applications such as heating, ventilating, and air-conditioning control; fire and other life safety and security systems; energy management; lighting control; physical access control; and elevator monitoring systems.

The BACnet protocol provides mechanisms by which computerized equipment of arbitrary function may exchange information, regardless of the particular building service it performs. As a result, the BACnet protocol may be used by mobile and cloud-hosted devices, head-end computers, general-purpose direct digital controllers, and application-specific or unitary controllers with equal effect.

This protocol provides a comprehensive set of messages for conveying encoded building automation data between devices including, but not limited to

(a) hardware binary input and output values,
(b) hardware analog input and output values,
(c) software data values,
(d) schedule information,
(e) alarm and event information,
(f) trend and event logs,
(g) files,
(h) control logic,
(i) application specific data for a large range of building services, and
(j) network configuration including security.

Standard 135-2020 -- BACnet™--A Data Communication Protocol for Building Automation and Control Networks

The 2020 edition of Standard 135 includes many new capabilities and several clarifications.

135-2016.jpgThis protocol provides a comprehensive set of messages for conveying encoded building automation data between devices:

  • Hardware binary input and output values
  • Hardware analog input and output values
  • Software data values
  • Schedule information
  • Alarm and event information
  • Trend and event logs
  • Files
  • Control logic
  • Application specific data for a large range of building services
  • Network configuration including security


BACnet Secure Connect: A Secure Infrastructure for Building Automation

BACnet SC Whitepaper-cover.jpg

Read about a new proposal centered on secure communications exclusively using accepted IT best practices. The new technology is called "BACnet Secure Connect (BACnet/SC)" and is the subject of this white paper. The purpose of the paper is to generate awareness of a relatively substantial change to Standard 135 that has to do with building automation systems and communication security over public/open networks such as the Internet.


Momentum Press -- BACnet: The Global Standard for Building Automation and Control Networks

BACnet Momentum.jpg
This new book by H. Michael Newman, original chairman of the BACnet committee, explains how the BACnet protocol manages all basic building functions in a seamless, integrated way.

The book explains how BACnet works with all major control systems--including those of Honeywell, Siemens and Johnson Controls--to manage everything from heating to ventilation to lighting to fire control and alarm systems. Contractors, architects, building systems engineers and facilities managers must all be cognizant of BACnet and its applications. Learn more

Bacnet™ Today and the Smart Grid - 2013

BACnet Today.jpgpdf_icon.png  BACnet™ Explained, Part One
By H. Michael Newman

BACnet™ Explained, Part Two
By Grant Wichenko, P.Eng.

 Microgrids for Energy Reliability
By Dave Robinson

  Securing a Control Systems Network
By Carl Neilson

  Smart Grid and Building Operators
By Phil Davis

  Communicating Submeter Data Via BACnet
By David Bovankovich

What's Next for BACnet™ and the Smart Grid - 2012

Journal BACnet cover.jpgpdf_icon.png OpenADR Advances 
David G. Holmberg
, Girish Ghatikar, Edward L. Koch, Jim Boch. P. B16. Nov.

pdf_icon.png Electric Utilities and The HVAC Industry 
Mike Oldak
. P. B10. Nov.

pdf_icon.png BACnet for a City 
Steven T. Tom
. P. B4. Nov.

pdf_icon.png Demand Response and Light Control 
Scott Ziegenfus
. P. B20. Nov. 

BACnet™ Today & the Smart Grid - 2011

BACnet Today Cover.jpgpdf_icon.png  Information Model Standard for Integrating Facilities With Smart Grid 
Steven T. Bushby
 P. B18. Nov.

pdf_icon.png  Demand Response and Standards: New Role for Buildings in the Smart Grid 
David Holmberg
 P. B23. Nov.

pdf_icon.png  BACnet Alarming Revised 
Bernhard Isler
 P. B12. Nov.

pdf_icon.png Getting Smart on the Electrical Grid 
Ed Koch
, Roy Kolasa  P. B29. Nov.

pdf_icon.png BACnet: Operator Workstations 
Steven T. Tom
. P. B6. Nov.

ASHRAE Members enjoy free access to current and archived editions of ASHRAE Journal, including content that appears in BACnet™ Today. Simply login to the Members Only section to search, browse, and view articles from 1997-present.


Other Resources

ASHRAE Learning Institute Short Course: Introduction to BACnet™