Inductive proximity sensor using coil time constant for temperature compensation
US7173411B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 2004 |
| Grant date | Feb 6, 2007 |
| Priority date | — |
| Expiry date | Aug 5, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/9547
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Systems and methods are disclosed that facilitate determining coil temperature in a proximity sensor, such as an extended range inductive proximity sensor. Voltage measurements can be taken before, and during, damped oscillatory decay of a voltage in a resonant circuit in the proximity sensor to determine a value, γ, associated with an inductive time constant for the resonant circuit. The gamma value comprises information related to both inductance and resistance in the sensor coil, and can be employed to determine coil temperature. Derivation of the gamma value, and thus of coil temperature, can utilize a current pulse of a duration of approximately one RC time constant of the resonant circuit, thus mitigating current consumption by the proximity sensor during temperature assessment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.