Any pressure transducer which relies on a force collecting diaphragm for sensing pressure, will be sensitive to a change in orientation.
A pressure transducer diaphragm is designed to flex when a force is applied to it. If the diaphragm is orientated horizontally it will sag slightly under the force of its own weight. If the diaphragm is then flipped upside down it will sag in the opposite direction. The movement in the diaphragm will translate as a slight change in pressure when monitoring the output signal of the device.
The offset generated by a change of diaphragm orientation is commonly called the G Effect, since the force causing the offset is due to the gravitational pull on the diaphragm.
In high pressure transducers the diaphragm’s sensitivity to orientation is very small and almost undetectable, but in low ranges where the diaphragm has a comparatively larger surface area to thickness ratio, it is significant enough to be a noticeable effect on the sensor performance.
Since the G effect is a static value at a particular orientation the offset error can be easily trimmed out as long as the pressure transducer position is fixed.
For low range pressure transducers with a high measurement accuracy, it is usual to indicate the orientation of the device during factory calibration by adding a reference mark on the transducer body or to indicate it on the calibration report.