BACnet

BACnet:

BACnet – A Data Communication Protocol for Building Automation and Control Networks. Developed under the auspices of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), BACnet is now an American national standard, a European pre-standard, and a potential global standard. The protocol is supported and maintained by ASHRAE Standing Standard Project Committee 135.

BACnet is “a data communication protocol for building automation and control networks.” 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 (in BACnet’s case they are also on compact disk) that spells out what is required to conform to the protocol.

BACnet provides a standard way of representing the functions of any device, as long as it has these functions. Examples are analog and binary inputs and outputs, schedules, control loops, and alarms. This standardized model of a device represents these common functions as collections of related information called “objects,” each of which has a set of “properties” that further describe it. Each analog input, for instance, is represented by a BACnet “analog input object” which has a set of standard properties like present value, sensor type, location, alarm limits, and so on. Some of these properties are required while others are optional. One of the object’s most important properties is its identifier, a sort of numerical name that allows BACnet to unambiguously access it. Once devices have common “appearances” on the network in terms of their objects and properties, it’s easy to envision messages that can manipulate this information in a standard way.

http://www.scadaengine.com/