METHOD OF REFERENCE POINT RETURN

摘要

Provision is made of a counter (16b) which counts, depending upon the rotational direction, the pulses (PF) generated every after a motor (15) for driving the mechanical moving part has turned a predetermined angle, and which further stores counts even when the power source is interrupted. The mechanical moving part is positioned at a reference point by manual feeding such as jog-feeding or handle-feeding, and a count NR of the counter (16b) at that moment is stored in a nonvolatile memory or in battery backed-up RAM (11c) contained in an NC apparatus (11). If a count of the counter (16b) at the time of switching on the power source is denoted by NA, return operation to the reference point is initiated upon receipt of a reference point return request and is stopped when the count of the counter (16b) reaches NR.