Inclinometer sensing circuitry and operation
US5428902A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 24, 1994 |
| Grant date | Jul 4, 1995 |
| Priority date | — |
| Expiry date | Feb 24, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C2009/182
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Measurement circuitry for a biaxial inclinometer having electrolytic fluid incorporates a Schmitt trigger for measuring the resistance of each leg of the inclinometer by measuring the frequency output of the Schmitt trigger circuit while each leg is placed across input and output terminals. Switching is accomplished by cycling analog multiplexers as solid-state switches under control of a microprocessor. To minimize net dc current across any leg, legs are periodically reversed in polarity as they are switched into the Schmitt trigger circuit for measurement. Additionally, in the wiring of the switching multiplexers to the inclinometer legs, an additional analog multiplexer is switched to place a low clamp resistance in parallel with each leg not being measured in a cycle, to compensate for leakage current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.