SHAPE MEASURING APPARATUS

摘要

PURPOSE:To achieve a higher reliability by forbidding the storing of a surface position data by a distance signal detected when a detection signal of a distance sensor is abnormal to move the distance sensor by one pitch in a tangential way orthogonal to a preceding direction of normal. CONSTITUTION:This apparatus is provided with an abnormality detecting means 507 which judges whether an output of a distance sensor 501 is abnormal or not and outputs an abnormality signal when it is abnormal and a forbidding means 508 which forbids the writing of a surface position data computed currently into a memory means 506 when the abnormality signal is outputted. When no abnormality signal is outputted, a direction of detection with the sensor 501 is turned to a direction of normal computed currently while a distance between an object W to be detected and the sensor 501 is set to a target value and a driver 504 is controlled so that the sensor 501 is moved by one pitch in a tangential way along an X axis orthogonal to the direction of normal. When the detection signal of the sensor 501 is abnormal, the storing of the surface position data by a distance signal detected is forbidden 508 and the sensor 501 is moved by one pitch in a tangential way orthogonal to a preceding direction of normal to the subsequent measuring point.