| 摘要 |
<p>System for returning a movable object (TB) to an origin by moving it towards the origin after it has been moved either toward the origin or away from it (+X direction). A dog (DG) is provided at one end of the movable unit (TB) and a machine stationary unit (MC), and a limit switch (LS) is provided at the other. This method comprises the steps of checking whether the limit switch is ON or OFF to discriminate whether the limit switch exists in an origin vicinity range (A II) on the basis of ON or OFF, in an overtravel side range (A I) at both sides of the dog or in a working range (A III), moving the movable unit (TB) toward the origin to a predetermined distance when the limit switch is not in contact with the dog, checking whether the limit switch is in contact with the dog or not by the movement, discriminating whether the limit switch is disposed at the overtravel side (A I) or at the working range side (A II), moving the movable until the limit switch is isolated from the dog when the limit switch is disposed at the overtravel side or in the vicinity of the origin, and moving the movable unit toward the origin when the limit switch is disposed at the working range or isolated from the dog in order to return to the origin. </p> |
