Abstract: A data transfer system in which a programmable sequence controller, a computerized numerical controller and a pair of data transfer devices are associated respectively with the controllers. Each of the transfer devices includes a data memory and a first read-out and write-in circuit for exchanging control data between the data memory and the associated one of the controllers. Each of the transfer devices further includes a second read-out and write-in circuit which is enabled to operate when the first read-out and write-in circuit is inoperative, for exchanging control data between the data memory and the other controller, so that the control data is transferred from the sequence controller to the numerical controller, and vice versa.

Abstract: An automatic centering controller for centering the axis of a tool spindle of a numerically controlled machine tool on the axis of a reference circumferential surface of an article mounted on the machine tool. The controller comprises a touch sensing device mounted in the tool spindle for detecting the touch of a probe thereof with the reference circumferential surface, a pulse generator for applying feed pulses to servomotors through a numerical controller so as to move the tool spindle along X and Y-axes, and a pulse control device connected to the touch sensing device, the numerical controller and the pulse generator.

Abstract: A device which detects the amount of displacement of a movable member moved by a feed device, and which outputs pulse signals corresponding to the amount of such displacement.

Abstract: A dressing apparatus for dressing a grinding wheel having straight and circular portions by a dressing tool which is moved by a pair of servomotors. A mode counter designates a mode of dressing operation on the straight and circular portions. A memory device stores numerical information to move the dressing tool along the circular portion. A gate circuit distributes clock pulses to both the servomotors in accordance with the content of the mode counter and the memory device, when the mode counter designates a dressing operation on the circular portion and distributes clock pulses to one of the servomotors in accordance with the content of the mode counter, when the mode counter designates a dressing operation on the straight portion.