What is a setpoint in BAS, and which are common examples?

• A. The current measurement from a sensor.
• B. The desired value for a controlled variable; examples: zone temperature, supply air temperature, chilled water exit temperature, damper position command, lighting level.
• C. A calibration constant.
• D. A historical log.

Answer: (B)

The setpoint is the target value for a controlled variable that the BAS aims to reach. The controller compares the actual measurement from sensors with this target and outputs commands to actuators to reduce the difference and bring the variable toward the setpoint.

Common examples include zone temperature (the desired air temperature in a zone), supply air temperature (the target temperature of air supplied by the air handler), chilled water exit temperature (the desired leaving temperature of chilled water for cooling), damper position command (the requested position of a damper to control airflow), and lighting level (the desired brightness level).

This is different from a current measurement, which is what the sensor reads in real time; a calibration constant, which adjusts sensor or sensor-system readings; and a historical log, which records past data.