Analog weighted binary absolute position encoder including an array of sense resistors each having material responsive to FWX and nonresponsive to flux
US5502380A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 28, 1994 |
| Grant date | Mar 26, 1996 |
| Priority date | — |
| Expiry date | Apr 28, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/8242
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnet mounted on a moving stem or rotary member of a valve generates magnetic flux over part of a stationary member of the valve which has an uniquely patterned set of magnetoresistive sense resistors and three reference resistors (the sensor) disposed thereon. The distance between two adjacent patterns can be equally spaced, or can be compressed for valves with non-linear characteristics in order to achieve increased resolution over a specific portion of the valve travel. Other embodiments can use a light source, beta radiation or neutron radiation as the source of flux, the pattern for each embodiment's sensor having some material responsive and some unresponsive to the flux. The sensor can provide feedback representative of position in a valve positioner, or functions as the position sensor in a position transmitter. Reference resistors provide a first signal representative of the resistance of a sense resistor in the absence of the flux and a second signal representative of the additive resistance of a sense resistor which is caused by the flux. An A/D circuit connected to the sense resistors differences the sensed resistance of each sense resistor with the first signal to c…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.