there is two types of bms field devices Sensors and Actuators as flowing :

Sensors :

• A sensor is a device that detects and responds to some type of input from the physical environment.
• The specific input could be light, heat, motion, moisture, pressure, ….etc.
• The output is generally a signal that is converted to human-readable display at the sensor location or transmitted electronically over a network for reading or further processing.

Actuators:

• An actuator is a component of a machine that is responsible for moving and controlling a mechanism or system, for example by opening a valve.
• In simple terms, it is a “mover”.
• An actuator requires a control signal and a source of energy.

below are some examples of bms field devices :

Diff. Press. Switch (DPS):

• Function: To indicate the Air Flow or the status of the filter (Dirty or clean).
• No Power, Dry Contact.

Air Diff. Press. Transducer:

• Function: To measure the differential pressure of the Air between two points on the Duct, or Areas .
• 24 V power, 0-10 VDC.

Duct or Pipe Temp. Sensor:

• Function: To measure the Air temperature in duct or water in pipe.
• No Power , Resistance .

Duct Hum Sensor:

• Function: To measure the Air humidity in the duct.
• 24 V power , 0-10 VDC .