What are the common BACnet object types for HVAC control?

The most frequently used BACnet objects in HVAC include Analog Input (AI) for sensor readings like temperature and pressure, Analog Output (AO) for actuator commands, Analog Value (AV) for setpoints and calculated values, Binary Input (BI) for status contacts like fan proof and filter differential switches, Binary Output (BO) for start/stop commands, and Binary Value (BV) for software enable/disable points. The Schedule object is critical for occupancy scheduling, the Trend Log object for historical data collection, and the Notification Class object for alarm routing and escalation. Per ASHRAE 135, Multi-state Input and Output objects are used for discrete operating modes (e.g., Occupied/Standby/Unoccupied) and Command objects are available for multi-action sequences like morning warmup.