Hi,
The single ported versions of the MPXV7002 are all Gauge Pressure sensors, which means that the reference pressure is open to local atmospheric pressure.
The reference pressure ‘port’ on Gauge sensors is an open hole in the bottom of the sensor, while port ‘P1’ is the one used to attach to the hose to measure the pressure.
You need to make sure that the differential pressure between port P1 and reference pressure is never higher than 75kPa.
Regards,
Jose