| 摘要 |
PURPOSE:To reduce the variance of the reading error and at the same time simplifying the measurement of an angle, by realizing an automated method so that an index is held between two scale lines. CONSTITUTION:A linear scale 21 on a scale disk 1 of theodolite, etc. is projected at the position of 22 via prisms 7 and 8 plus lenses 8 and 9 so as to be put in parallel to a scale 23 at the position away from the position 22 by 180 deg.C. The parallel scales 22 and 23 form an image at a detection part 17 through a prism 10, a lens 11 and a parallel plane glass 12. A microprocessor 35 actuates a pulse motor 14 via a motor driving circuit 36, and the reference position of the motor 14 defined when the glass 12 has its maximum swing angle. This reference position is detected by a detecting circuit 37. The processor 35 displays 38 the angle information of the disk 1 via a detection element 31, a differential amplifier 32 and zero-cross detecting circuit 33 and by the outputs given from an absolute encode pattern-to-gray code exchanging circuit 34 and the circuit 37 respectively. |
