Sometimes it is not necessary to monitor the absolute air pressure but we need to know the difference of pressures in different points. One example may be before and after a valve in a pipe. If the valve is fully open, the pressure on both sides should be the same. If there's a difference in the pressure, it could be the valve isn't fully open or there's a blockage.
Differential Pressure Sensor has two air pressure inputs. It monitors the pressure difference between these two inputs and put the value.
Differential Pressure Sensors can be used in home and industrial environments for applications such as offshore and subsea gas processing, and remote heating systems.
Dragino's Wireless Differential Pressure Sensor includes various model to cover LoRaWAN wireless transmission and different range of pressure measurement.