Detection device for position of circular table of machine tool, has correction unit correcting offset of signals based on correction value of offset, as correction value corresponds to absolute position and is selected from storage unit

摘要

The device has an offset correction unit for correcting an offset of two phase signals output by a precision position sensor (2). An offset correction value storage unit (32) stores a correction value of offset for the two phase signals according to an absolute position. The offset correction unit corrects the offset of each of the two phase signals based on the correction value of offset, as the correction value corresponds to the absolute position, and is selected from the offset correction value storage unit.