To improve the reliability of initial data detected at the time when a power supply is turned on and the input time of a required signal by reading the absolute-value pattern a plurality of times even when relative movement is generated between a code plate and a detecting part.
Signals k1 and k2 from an incremental sensor 5 are outputted to a control circuit 7. The bit signal from an absolute-value sensor 6 is stored in shift registers 8-10. The control circuit 7 detects the rotating direction of a code plate 1 with respect to a detecting part 2 from the signals k1 and k2 and outputs clock signals s-u in correspondence with the rising or falling of the signal k1. The sensor 6 sequentially scans the detected signals by a scanning signal (a) of the control circuit 7 and outputs bit signals B1-B4 in serial. A comparing and judging circuit 11 outputs an agreement signal (f) when absolute signals C-E of the shift registers 8-10 agree, detects the rotating direction based on the signal k1 and k2, changes a signal C of the initial value and outputs absolute-value data H to the outside.
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| WO/2009/119471 | MAGNETIC SENSOR AND MAGNETIC ENCODER |
ONO YASUSHI
TAKAHASHI YOSHIJI
IMAI MOTOMASA
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