Objects are self-contained functional items in the systems that contain processes to manage building automation system components. Objects appear as items in the Navigation Tree that shows the hierarchical physical or logical relationship between the objects as created by the user. These objects are generally referred to as items in the user interface.
Each object that exists in a system is based on a specific object type. There is an object type to manage the functions of the site, object types to manage the operation of the various device types installed on the site, object types to manage the physical input/output points of each field device, and others.
Objects communicate with the rest of the system and with the user through their attributes. The object type defines the basic function of the object, but the actual behavior of each object also depends on the values assigned to its configuration attributes and received by its input attributes from other objects. The object writes its status conditions and the results of internal processes to its output attributes.
When an object type has an equivalent BACnet Object Type, the attribute list includes the BACnet Properties required by the BACnet protocol specification and some of the optional properties. These objects may be accessed from a BACnet network. For detailed information on BACnet objects and properties, refer to ANSI/ASHRAE Standard 135-2008 - A Data Communication Protocol for Building Automation and Control Networks.