Which of the following are core hardware components of a BAS?

• A. Controllers, sensors, and actuators
• B. Controllers, sensors, and meters
• C. Sensors, actuators, and meters
• D. Controllers, actuators, and meters

Answer: (A)

A BAS is a closed-loop system that senses the environment, processes information, and acts to control conditions. The essential hardware trio that makes this possible are sensors, controllers, and actuators. Sensors gather data such as temperature, humidity, and occupancy. Controllers analyze those readings against setpoints or rules and decide what needs to be done. Actuators carry out those decisions by adjusting equipment like dampers, valves, or relays to influence the building systems.

Meters can be useful for monitoring energy use and performance, but they are measurement tools rather than the active parts of the control loop. They don’t sense conditions or directly drive changes in the environment, so they aren’t considered core hardware for the BAS’s control function.

If any of the core three are missing, the system can’t operate as a true BAS: without a controller there’s no processing of data and no actionable decision; without sensors there’s no data to act on; without actuators there’s nothing to change in the building.