What is a building automation system input?

• A. A device that senses and sends building condition information to a controller.
• B. A device that stores configuration data.
• C. A device that powers sensors and actuators.
• D. A device that provides user authentication data.

Answer: (A)

In a building automation system, inputs are sensors or devices that measure conditions in the environment and send that information to the controller. They collect data such as temperature, humidity, occupancy, light level, or air quality and translate it into signals the BAS can read and process. This is why the option describing a device that senses building condition information and transmits it to the controller is the best fit. Other roles described—storing configuration data, powering sensors and actuators, or supplying user authentication data—serve different functions (memory, power supply, and security), but they do not provide real-time condition data to the controller.