Ace Controls Limited

What is BACnet?

BACnet is an acronym for Building Automation and Control networks. It is the name for an ASHRAE and ANSI standard data communication protocol, which is a set of rules governing the exchange of data over a computer network. The rules govern hardware (for example, cable types, system topology) and software (for example, formation of request or command messages). The rules are in a published specification (ANSI/ASHRAE Standard 135-2004) that defines what is required to conform to the protocol



The BACnet specification also defines the BACnet components: the object and services model, the network layer protocol, and a selection of various network transport technologies. (See Table 1.) As a result, the BACnet specification can govern the design of workstations, controllers, gateways, routers, and diagnostic tools. BACnet was designed specifically for all building automation applications:
HVAC control
Fire detection and alarm
Lighting control
Elevator interface
Utility company interface
To achieve these capabilities, BACnet specifies nearly all of the common building control and monitoring functions, for example: analog and binary inputs, outputs, and values; control loops; schedules, etc.
One of the strengths of BACnet is in accommodating future building automation applications. A vendor can easily add to the existing objects and services. This is not only expected, it is encouraged. Of course, for proprietary features to interoperate, vendor cooperation is required.
Thousands BACnet sites are already operating both in the USA and in various countries around the world.


Why BACnet was Developed
The idea for BACnet was fostered by building automation system (BAS) users within ASHRAE. They believed that BAS technology had progressed sufficiently that standards could be established such that products from different anufacturers could all work together. In other words, BACnet could enable control product interoperability. The benefits of nteroperability to BAS users are:
One workstation can work with remote panels and controls from different manufacturers
More competitive bidding on expansions and additions
Freedom to select the manufacturer(s) that best meet the requirements of the project at the best price
Allows the addition of technologies and services as they become available, regardless of manufacturer
A higher likelihood that a current system can be expanded without having to replace it entirely–thus protecting the control system investment
The benefits of BACnet to controls system manufacturers and suppliers are:
There is no charge (license fee) for its use–anyone is permitted to develop and use implementations without cost.
It is maintained by an ASHRAE committee representing all sectors of the industry.

  • It is designed specifically for building control.
  • It is designed to be implemented in devices of all sizes.
  • It is designed to be readily enhanced and improved.
  • Its design is not tied to present technologies.


How BACnet was Developed:

To develop BACnet, ASHRAE established a Standard Project Committee (SPC-135). The original BACnet standard was published in 1995. To help ensure acceptance, the standard had been thoroughly reviewed, studied and analyzed by the industry. The participants in the original testing became the National Institute of Standards and Technology (NIST) ACnet
Interoperability Testing Consortium.
BACnet was introduced at the ASHRAE Winter Meeting in January, 1996. In the BACnet booth at the show, equipment from ten different vendors running various types of computers, operating systems, and LAN types were successfully interconnected.
In 2001, the BACnet standard was updated with five addenda. In January 2003, the BACnet standard was approved as ISO Standard 16484-5 and as a European standard within the Committee for European Standardization (CEN).
The BACnet specification is maintained by ASHRAE Standing Standard Project Committee (SSPC) 135. This committee works on refining and expanding the standard.

Conformance of a product to the BACnet standard is the responsibility of an independent
organization called the BACnet Testing Labs (BTL). The BTL develops testing tools and
scripts to certify and list devices that conform to device profiles. The BTL consists of a core
group sponsored by the BACnet International (BI) and individual manufacturer participation.

BACnet Implementation within APOGEE
The goals of BACnet are:
Support ANSI/ASHRAE standard BACnet IP throughout field panel and workstation architecture.
Meet BTL requirements for the field panel and the workstation.
Meet the global strategic BACnet requirements of Siemens Building Technologies, Inc.
Maintain/Enhance APOGEE Automation System features, functionality, performance, look and feel.
Maintain APOGEE Automation System backward compatibility.


Contact Us