Although there are thousands of potentially useful object types which might be found in building automation, BACnet defines 23 standard object types in some detail. A BACnet standard object is one whose behavior, in terms of which properties it provides and what they do, is defined in the BACnet standard.
This set of standard objects represents much of the functionality found in typical building automation and controls systems today. BACnet devices are only required to implement the Device object. Other objects are included as appropriate to the device’s functions.