Patent ID: 11946779
Assignee: DMG MORI CO., LTD.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 4:
5. A position detection method comprising:
recording, in an absolute track, a first binary sequence generated from a second binary sequence; and
reading, by an absolute sensor unit, the first binary sequence from said absolute track,
wherein the first binary sequence consists of 0s and 1s and is generated by replacing 0 in the second binary sequence with 10 and 1 in the second binary sequence with 01, or by replacing 0 in the second binary sequence with 01 and 1 in the second binary sequence with 10,
wherein when reading, values in the second binary sequence are replaced with 1s and 0s in accordance with not a positive/negative of magnetism but a direction of inversion from positive to negative or from negative to positive, and
wherein said absolute sensor unit includes two sensor elements arranged at an interval of λ/2 or less than λ/2 of a recording pitch λ of the first binary sequence,
the method further comprising:
communicating, by an incremental track, with an incremental sensor unit that detects fore and rear positions of the absolute sensor unit;
generating, by an inverter, an inverted sequence by bit-inverting a detected sequence detected by said absolute sensor unit;
discriminating, by a discriminator, based on the fore and rear positions detected by the incremental sensor unit, which one of the detected sequence and the inverted sequence should be searched for;
searching, by a searcher, the second binary sequence for the detected sequence or the inverted sequence discriminated by the discriminator; and
detecting, by a position detector, a position of said absolute sensor unit based on a position of the detected sequence or the inverted sequence found by said searcher in the second binary sequence and the fore and rear positions detected by the incremental sensor unit.