Meeder,
Can you suggest a sensor ?
By the by a sensor which is exposed to the atmosphere will provide the differential pressure reading( between atmosphere and say water column plus atmosphere.
For the exact sensor type you would need more information. I think it is wise to contact a suplier to get the exact type you need.
What you call a differential sensor is what we call a relative pressure sensor.
Basically there are three types of sensor.
Relative, the side opposite to the process connection is open to the atmosphere.
Absolute, the opposite side is closed off.
Differential, this sensor typically has two process connections and is either connected through impuls lines connected directly to the process or capillaries with secondary membranes connected to the process.
https://youtu.be/QrT8VWxdxwk