Which statement best describes setpoint scheduling in a direct digital control system?

• A. Setting a fixed setpoint for all hours.
• B. Changing setpoints based on time or occupancy; example: lowering cooling setpoint at night.
• C. Automatically adjusting only humidity.
• D. Logging setpoints for audits.

Answer: (B)

Setpoint scheduling means adjusting the target conditions of a system over time to match how a space is used. In a direct digital control system, the controller can change setpoints based on the time of day or whether spaces are occupied so that equipment runs more when people are present and trims back when they aren’t. This is why describing setpoints as changing based on time or occupancy—for example, lowering the cooling setpoint at night—best captures how scheduling works. It shows actively steering temperature targets to balance comfort with energy efficiency, rather than sticking to a single fixed target. It’s not about adjusting only humidity, which is too narrow, nor about simply logging setpoints for audits, which is about records rather than controlling the environment.