Abstract: A positioning system rotates a servomotor (4) in response to a command value to move a movable unit and compares a feedback signal from a position detector, such as a servomotor or the like, with the command value to output a servo command signal. Pulses from an encoder (5) are counted to generate a positional information signal (6) directly indicative of an angular position of the servomotor (4), and the positional information signal is fed back to a command processor (2) to effect a positioning operation.

Abstract: A monitor device for a screw position and an internal die pressure is used by an injection molding machine for driving a screw (29) by a servo motor (27). During injection, a sequentially updated address from an address generator (20) is supplied to first and second memories (16, 18) through an address switching circuit (21) to designate addresses of the memories (16, 18) so that the output from a pulse counter (15), which represents the screw position, and the output from an analog/digital converter (17), which represents the internal pressure of a die (30), are sequentially stored in the first and second memories (16, 18). During monitoring, the values stored in the first and second memories (16, 18) are read out through the address switching circuit (21) which has performed switching, and the relationship between the screw position and the internal die pressure is displayed on a display unit (25).

Abstract: A memory data holding circuit for ensuring holding of the stored contents of a memory even if power happens to be turned OFF when the memory is being accessed. A first detecting circuit (2) detects the turning-OFF of the power supply, and a second detecting circuit (7) detects whether a memory (1) is being accessed or not. A switching circuit (8) supplies an operating current from a backup power supply (3) to the memory (1) only when the first detecting circuit (2) detects that the power supply has been turned OFF and the second detecting circuit (7) detects that the memory is not being accessed. An access inhibit means (5, 7) inhibits access to the memory (1) only when the first detecting circuit (2) detects that the power supply has been turned OFF and the second detecting circuit detects that the memory is not being accessed, so that access to the memory (1) is prevented being discontinued before access is completed.

Abstract: A method and apparatus for numerically controlling a machine tool having at least two tools which are arranged to move in unison with a constant position relationship with respect to one another, the tools being moved relative to a workpiece in accordance with absolute commands to machine a workpiece in a prescribed manner. A single current position register, comprising a section for storing X coordinates and a section for storing Z coordinates, is provided to store the current position of a first tool. Further provided are arithmetic means, responsive to a command for setting coordinates, for computing the current position of a second tool, as well as pulse distribution means.