| 摘要 |
PURPOSE:To obtain absolute position data within a reduced moving range by a simple means, by employing A- and B-phase incremental systems having predetermined phase difference and generating Z-phase pulses having pulse widths different in the width equal to or more than several pulses of each of A- and B-phases with the movement of a moving body. CONSTITUTION:A rotary disc 2 is mounted to the shaft 1 rotating with the movement of a moving body. 90 slits each 3A and 3B for A- and B-phase 3A, 3B and Z-phase slits 3Z (Z1-Z6) are respectively provided to said disc 2 by drilling. The pulse widths of the slits Z1-Z6 are different from each other and respectively correspond to the moving position (angle of rotation) of the moving body. Light emitting elements 4A-4Z correspond to A-Z-phase slits 3A-3Z and the photoreceptors 5A-5Z are arranged in opposed relation to the elements 4A-4Z through the disc 2. Therefore, by one revolution of the disc 2, 90 pulses each for A- and B-phase having 90 deg. phase difference are outputted from the photoreceptors 5A, 5B and 6 Z-phase pulses different in a pulse width are outputted from the photoreceptor 5Z. |
