Abstract: A numerical control system for a machine tool having a plurality of saddles; comprising saddle discriminating means for discriminating the saddles from each other, in which saddle discriminating means the cutting work program for controlling the machine tool is described by the use of the same word addresses for each of the saddles but by adding codes for discriminating the saddles from each other at the head of the respective words indicating the same word addresses.

Abstract: In a position-correctable numerical control system for machines without any device for detecting the absolute position of an object to be controlled, a plurality of equidistantly-spaced reference marks providing standard ranges of control of the object are determined by a reference mark detection pulse generator. Reference positions corresponding to the reference marks are stored in advance in a non-volatile memory. The actual position of the object is compared with a reference position stored in said non-volatile memory, each time the object to be controlled passes each of the reference marks, so that the actual position of the object is corrected in accordance with a difference, if any, between the actual position and the reference position.