Patent ID: 8175743

Claim:
A measurement system comprising: an industrial machine, comprising: a relative movement member on which a measuring element that is used for measuring a target object or a machining device that is used for machining the target object is mounted, either the relative movement member or the target object moving relative to the other, a table adapted to receive the target object, a moving mechanism that either moves the relative movement member relative to the target object or moves the table so as to move the target object relative to the relative movement member, and a stopping section; and an interferometer, comprising: a measurement unit that includes a reflector, a light source, and a light reception unit, the light source emitting light toward the reflector, which is attached to the relative movement member, the light reception unit receiving light reflected by the reflector, the measurement unit generating a received-light signal upon receiving the light and outputting the received-light signal, and an information processing unit that calculates a distance from a reference point inside the measurement unit to the reflector based upon the received-light signal, the information processing unit comprising: a judging section, and a stop command outputting section, wherein the relative movement member moves relative to the measurement unit in a case where the moving mechanism moves the relative movement member relative to the target object, whereas the measurement unit is mounted on the table and moves relative to the relative movement member in a case where the moving mechanism moves the table so as to move the target object relative to the relative movement member, wherein the judging section of the information processing unit judges whether there is any abnormality in measurement targeted at the reflector based upon the received-light signal, wherein the stop command outputting section of the information processing unit outputs a stop command for instructing that driving operation of the moving mechanism should be stopped when it is judged by the judging section that there is abnormality in measurement targeted at the reflector, and wherein the stopping section of the industrial machine stops the driving operation of the moving mechanism upon receiving an input of the stop command.