| 摘要 |
PURPOSE:To always perform the correct positioning by having comparison between the difference of positions of mobile parts corresponding to the detection signal of a position detecting means and the signal which is produced for each rotation of a pulse code. CONSTITUTION:A pulse coder 17 produces a pulse (a-signal) and plural pulses (b- signal) for each revolution of a motor 11 and sends these pulses to a controller 18. At the same time, the position detecting signal of a limit switch 16 set approximate to a mobile part 14 is also sent to the controller 18. The controller 18 counts the number of pulses of the signal (b) between the rear edge of the position detecting signal and the signal (a) existing immediately after said rear edge. This count value is compared with the reference value of a memory 19. When the difference obtained from this comparison is larger than the prescribed level, an alarm device 20 is actuated. At the same time, the position data of an original point is shifted with actuation of a correction routine, and the contents of the memory 19 are replaced. In such a way, the correct positioning is always possible. |
