Electronic interface for use with dual electrode capacitance diaphragm gauges
US6734659B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 13, 2002 |
| Grant date | May 11, 2004 |
| Priority date | — |
| Expiry date | Jun 13, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L9/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Systems and methods for determining differential currents in a pair of circuits. In a preferred embodiment, an excitation voltage and a tightly coupled differencing current transformer are coupled to a differential capacitance manometer to generate a differential current. This differential current is input to a low-impedance summing node of a charge amplifier that effectively integrates the differential current. A shielding structure surrounding the current transformer and amplifier is driven to the excitation voltage potential. The output of the charge amplifier is passed through a common mode transformer which is coupled to the excitation voltage source in order to remove the guard potential (corresponding to the excitation signal) from the output signal. A synchronous detector then converts the resulting signal to a DC level indicative of the differential capacitance of the sensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.