What are two common sensor outputs used in BAS sensors and what do they indicate?

What are two common sensor outputs used in BAS sensors and what do they indicate?

• A. 12 V DC digital outputs indicate measured quantities; analog sine wave outputs indicate binary states.
• B. 0-10 V or 4-20 mA analog outputs indicate measured quantities; digital on/off outputs indicate binary states.
• C. MQTT topics indicate measured quantities; REST endpoints indicate binary states.
• D. Ethernet frames indicate measured quantities; USB signals indicate binary states.

Answer: (D)

Sensors in building automation typically use two common outputs: analogue and digital. Analogue outputs, like 0–10 V DC or 4–20 mA current loops, carry a continuous value that represents a measured quantity such as temperature, humidity, or pressure. This lets the controller read precise, ongoing measurements. Digital outputs are on/off signals that indicate a binary state—think valve opens or closes, a switch is active, or a sensor is triggered. These directly convey simple conditions that the system can act on. Ethernet frames or USB signals aren’t the direct sensor outputs used to convey a measurement or a binary state. They’re network and interface methods for transmitting data, not the fundamental physical quantity or state the sensor is meant to indicate.

Sensors in building automation typically use two common outputs: analogue and digital. Analogue outputs, like 0–10 V DC or 4–20 mA current loops, carry a continuous value that represents a measured quantity such as temperature, humidity, or pressure. This lets the controller read precise, ongoing measurements. Digital outputs are on/off signals that indicate a binary state—think valve opens or closes, a switch is active, or a sensor is triggered. These directly convey simple conditions that the system can act on.

Ethernet frames or USB signals aren’t the direct sensor outputs used to convey a measurement or a binary state. They’re network and interface methods for transmitting data, not the fundamental physical quantity or state the sensor is meant to indicate.