| 摘要 |
<p>PURPOSE:To detecting the moving direction of an object with one set of sensor by successively generating different waveform signals in preset order as the object moves and discriminating the order of the generated signals. CONSTITUTION:While a disk 6 rotates, one set of sensor detects slits 7-9 which move together with the disk 6. For example, the eight slits are arranged along eight lines dividing the circumference of the disk 6 into eight equal parts so that the number of detected slits can become proportional to the rotational angle of the disk 6. The slit 7 has the narrowest width and the slit 9 has the widest width, with the slits 8 having intermediate widths, and the slits 7-9 are arranged so that their widths can become successively wider. Pulses 10-12 having different pulse widths in corresponding to the widths of the slits 7-9, with the pulses 10 and 12 respectively having the narrowest and widest widths, are repeatedly arranged in string from the pulse 8 to pulse 10. The width of the pulse 12 is set at about threefold of that of the pulse 10. The pulse string is fetched to a CPU and the CPU discriminates that the rotating direction of the disk 6 is normal (reverse) when the pulse widths become wider (narrower). While the pulse widths become narrower at the changing point from the pulse 12 to the pulse 10 even when the rotating direction is normal, the direction is discriminated as normal (reverse) when the pulse widths become narrower (wider) than the half of the preceding one.</p> |
