Fujitsu Fanuc Limited

Fanuc Corporation

Hiroomi Fukuyama

Shinichi Isobe

Ryoji Imazeki

Mikio Yonekura

Yoshihiro Nakashima

Yoshimasa Kagawa

Minoru Kataoka

Kiyoshi Hattori

Masahiro Kaku

Numerical control unit

Tool display system of automatic tool changing apparatus

Screw cutting control system

A method of diagnosing a servomotor position control circuit which includes a pulse distributor for carrying out arithmetic operations for pulse distribution based on command data given by a control unit, a position detector for generating a positional pulse each time the servomotor rotates through a predetermined angular interval, an error storage unit for computing and storing the difference between the number of positional pulses generated by the position detector and the number of distributed pulses generated by the pulse distributor, and a D/A converter for converting the difference into an analog output, whereby the servomotor is controlled by the analog output from the D/A converter. The method comprises the steps of supplying a numerical value from the control unit to the pulse distributor to enable the latter to effect the arithmetic operations while the servomotor is being de-energized, reading a stored content of the error storage unit, supplied with the distributed pulses from the pulse distributor, into the control unit, and checking the servomotor position control circuit for normal and malfunctioning conditions by comparing the stored content as read by the control unit with the numerical value.

Method of diagnosing a servomotor control circuit

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. The method includes the steps of storing the position of the first tool in the current position register prior to machining the workpiece with the first tool, moving the first tool to machine the workpiece in accordance with the current position and an absolute command, computing the current position of the second tool via the arithmetic means in response to the command for setting coordinates to change control from the first tool to the second tool, storing the computed current position in the current position register, and moving the second tool to machine the workpiece in accordance with the content of the current position register and an absolute command.

Method and apparatus for a numerical control device for controlling a

Method of constant peripheral speed control

A feed speed control system for use in numerical control systems or the like, in which a set feed speed can be adjusted through a simple structure. The control system includes a memory circuit for storing a plurality of numerical values corresponding to feed speeds, a command circuit for issuing a command indicative of a prescribed numerical value from among the plurality of numerical values, an arithmetic circuit for incrementing or decrementing a numerical value read from the memory circuit in response to an output pulse from manual operation device, and a pulse generating circuit for generating pulses of a frequency which is proportional to an incremented or decremented numerical value from the arithmetic circuit.

Feed speed control system

A method and system for transmitting N-bit serial data (where N is a positive number) in the form of a bit serial, including a data sending circuit, a data receiving circuit and data transmission lines. The system includes a first data transmission line; a second transmission line; a transfer circuit, provided in the receiving means, for sending back to the data sending circuit through the second data transmission line, the bit content of received N-bit data each time one bit of the N-bit data is received through the first data transmission line; a comparison circuit, provided in the data sending circuit, for comparing the transmitted bit content and the bit content sent back on the second data transmission line; and a detection circuit provided in the data receiving circuit. The data sending circuit is adapted to transmit as a start bit a signal of a prescribed logical value before the N-bit serial data is sent, and, as an alarm bit, the results of the comparison after the N-bit serial data has been sent. The detection circuit detects whether the logical values of the start bit and the alarm bit are prescribed logical values, so that a transmission error or a break in a transmission line can be detected.

Method and system for transmission of serial data

When machining with a numerical-controlled machine tool, both a command value providing the configuration of a finished product and a compensation value depending on the tool are needed, and tool compensation data must be corrected in response to tool wear. The present invention, taking notice of the fact that correction data corresponding to tool wear can be predetermined from the frequency or time of tool use and the fact that the amount of tool wear can be unequivocally determined by the quality of materials of the tool and work, provides circuitry for counting the frequency or time of use of the tool and circuitry for correcting by a predetermined value the content of a compensation value register having tool compensation date when the number of times a tool has been used or when the duration of tool use has reached a predetermined value.

Tool compensation system

In a numerical control unit which has an interpolation function from generating command pulses in response to a distribution command and a servo system for driving a movable part of a machine in accordance with command pulses, a comparison is made between the error of the servo system a predetermined period of time after the distribution command is switched off and a preset value; when the error of the servo system is larger than the predetermined value, an alarm signal is produced to detect the occurrence of a malfunction.

Malfunction detecting system

A positioning system in a numerically controlled apparatus in which a position of a controlled object such as table and tool is controlled by command pulses delivered from the numerical control apparatus. The positioning system

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Hachioji, Japan

Hiroomi Fukuyama