Liquid level sensor incorporating a capacitive rotary position encoder
US5941122A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 1997 |
| Grant date | Aug 24, 1999 |
| Priority date | — |
| Expiry date | Dec 4, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/2415
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A circuit board has an arcuate array of conductor segments each subject to a digital waveform differing in phase for the various segments, and a concentric pickup conductor. A rotary encoder disk has a conductive pattern which sums and couples the waveforms from selected segments, depending on rotary position, to the pickup conductor. A synchronous phase detector generates a phase signal from the summed waveforms and the zero crossing of the phase signal is detected. A counter develops count signals used to generate the digital waveforms. The count signals are input to a latch which is clocked at the zero crossing point to latch the count value which is a digital measure of the encoder angle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.