PURPOSE: To provide a numerical control system which can prevent cutting mistakes, etc., by occasionally checking the validity of present position data of a machine that is contained in a numerical controller.
CONSTITUTION: The position data on a machine 16 under machining are always held by a present value register means 17. A sensor means 20 is attached to the machine 16 to output a detection signal when the machine 16 reaches a prescribed position. The position data on the machine 16 are stored in a parameter storage means 19. When the detection signal is received from the means 20, a comparison means 18 compares the data stored in the means 17 with the data stored in the means 19. Then, an error signal is outputted when the difference between both data is not kept in an allowable range, and the operation of the machine 16 is automatically stopped.
KOZAI HARUHIKO
MIYAKE MASAHIKO
