Method and apparatus for feedback-control of an asymmetric differential pressure transducer
US5641911A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 4, 1994 |
| Grant date | Jun 24, 1997 |
| Priority date | — |
| Expiry date | Oct 4, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L11/008
- WIPO fieldMeasurement
- WIPO sectorInstruments
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 ampl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.