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 .