Measuring and testing – Fluid pressure gauge – Diaphragm
Patent
1994-10-04
1997-06-24
Chilcot, Richard
Measuring and testing
Fluid pressure gauge
Diaphragm
73715, 73724, G01L 900
Patent
active
056419112
ABSTRACT:
The invention is related to a feedback method and apparatus for a capacitive differential pressure transducer. According to the method, a pressure-transducing conducting diaphragm (1) forming a first, moving electrode of the transducer capacitances is kept in a force balance state by means of a pulse train signal applied to a fixed electrode (2, 3). According to the invention, the diaphragm (1) is kept stationary in a geometrically constant state and a desired electric potential is applied to the diaphragm (1), the pulse train signal is applied to at least two of the fixed electrodes (2, 3), or alternatively, sets of fixed subelectrodes. The signals applied to separate electrodes (2, 3) or sets of subelectrodes are at opposite polarities referenced to the electric potential of the pressure-transducing diaphragm (1) for at least a portion of the measurement duration, and are of equal amplitude at least for each pair of electrodes (2, 3). The same pulse train signal is simultaneously used for both establishing the force balance and performing the capacitance measurement. Changes in the dielectric coefficient of the transducer fill medium are compensated for by altering the pulse amplitude, pulse width or pulse rate depending on the primary modulation method used in the feedback control.
REFERENCES:
patent: 4434664 (1984-03-01), Antomazzi
patent: 4831492 (1989-05-01), Kuisma
patent: 5095750 (1992-03-01), Suzuki et al.
patent: 5377524 (1995-01-01), Wise et al.
patent: 5531128 (1996-07-01), Ryhanen
Semiconductor Capacitance-type Accelerometer with PWM Electrostatic Servo Technique, Sensors and Actuators, A21-A23, 1990, Suzuki et al., pp. 316-319.
Design and Test of a Precision Servoaccelerometer with Digital Output, The 7th International Conference on Solid-State Sensors and Actuators, Y. de Coulon et al., 1993, pp. 832-835.
Wise, Kensall D., Analog Data Acquisition Circuits In Integrated Sensing Systems, in Advances in Analogue Circuit Design, Apr. 6-8, 1993, edited by Sansen, Huijsing, and van de Plassche. Apr. 8, 1993.
Biegel Ronald
Chilcot Richard
Vaisala Oy
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