Cross coil type indicator
US5119320A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 4, 1989 |
| Grant date | Jun 2, 1992 |
| Priority date | — |
| Expiry date | Aug 4, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R7/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In a cross coil type indicator having a pair of cross coils arranged in quadrature, a magnet rotor having a shaft and a pointer attached to the shaft and rotatably positioned within the coils, the pointer is positioned to indicated a variable by flowing pulse currents through the coils in which the duty ratio is related to the variable value. Digital data corresponding to the pointer angle is stored as sin .THETA. or cos .THETA. data in a read only memory to enable simple calculation of pointer position from the duty ratio of the current pulse. A stop pin is provided to limit rotation of the pointer at the end of the scale; a circuit is provided for determining when the pointer is adjacent to the pin or will be driven against the stop pin, and the drive currents are modified in response to such conditions to reduce repetitive striking of the pin by the pointer and to minimize the force with which the pointer is driven against the pin at the stop pin end of the scale.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.