Patent ID: 8862420

Claim:
A method for compensating for effects of gravity on the diaphragm of a capacitance diaphragm gauge (CDG) that measures an absolute pressure applied to an input of the CDG, wherein the CDG is positionable with the diaphragm in differing orientations with respect to the earth's surface, the method comprising: applying an applied absolute pressure to the input of the CDG; generating a measured pressure value responsive to the applied absolute pressure; determining an orientation of the CDG with respect to the earth's surface using a tilt sensor coupled to the CDG; and adjusting the measured pressure value by a calibration factor determined by the orientation of the CDG to generate a calibrated pressure value that corresponds to the applied absolute pressure, wherein the calibration factor is determined by: applying a known absolute pressure to the input of the CDG; varying the orientation of the CDG with respect to the earth's surface to a plurality of different orientations while monitoring the measured pressure value at each of a plurality of different orientations; determining a difference between the measured absolute pressure and the known absolute pressure at each of the plurality of different orientations; and generating a respective calibration factor for each of the plurality of different orientations based on the difference between the measured absolute pressure and the known absolute pressure at each respective orientation.