Overview of BACnet

BACnet is a non-proprietary system, initially developed through the combined efforts of both building management system vendors and customers. According to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standing Standard Project Committee 135, BACnet is "a data communication protocol for building automation and control networks." Also according to ASHRAE, BACnet, "is an American national standard, a European standard, a national standard in more than 30 countries, and an ISO global standard." For more information about BACnet, please visit www.bacnet.org.

A data communication protocol is a set of rules governing the exchange of data over a computer network. The rules take the form of a written specification that spells out what is required to conform to the protocol; they govern the exchange of data over a computer network. These rules spell out what is required to conform to the BACnet protocol. What makes BACnet unique is that its rules relate specifically to the needs of building automation and control equipment; they cover things like how to ask for the value of a temperature, define a fan operating schedule, or send a pump status alarm. Common BACnet applications include HVAC controls, fire detection and alarm, lighting control, security, "smart" elevators and utility company interfaces.

BACnet Client-Server Architecture

BACnet is based on a client-server model. BACnet messages are called "service requests." A client machine sends a service request to a server machine that then performs the service and reports the result to the client. BACnet currently defines 35 message types that are divided into 5 groups or classes.

One class contains messages for accessing and manipulating the properties of the objects described above. A common message is the "ReadProperty" service request. This message causes the server machine to locate the requested property of the requested object and send its value back to the client. Other classes of services deal with alarms and events; file uploading and downloading; managing the operation of remote devices; and virtual terminal functions.

ICONICS BACnet solutions integrate BACnet communications into the GENESIS64 and GENESIS32/Workbench32 product families. ICONICS BACnet solutions address customers' facility monitoring needs. Facility Engineers, facility managers and others involved with building management will appreciate its integration with ICONICS GENESIS64 HMI/SCADA and GENESIS32/Workbench32 suites.

Note that ICONICS is compliant with ANSI ASHRAE Standard 135-2008.

NOTE: Types which are part of the specification above are supported by ICONICS as well as other BACnet standards. ICONICS supports read/write property for all BACnet objects, but only the objects defined in ANSI ASHRAE Standard 135-2008 would be correctly shown in ICONICS clients (e.g. GraphWorX64).

To start working in ICONICS BACnet-related applications, use the following topics as a roadmap: