Numerical control system

Claim 2

A numerical control system for directing a mechanism for controlling the displacement of a controlled quantity along at least one axis comprising: a part program source for holding in storage a segmented program defining the overall parameters of a controlled function to be performed including the contour of a path to be traced by said controlled quantity, a programmable digital processor; said processor including a control program in memory; a plurality of devices including said source and at least one interpolator for transferring segments of said segmented part program toward the mechanism for direction thereof along said axis; each of said devices having a digital address; said processor being connected to each of said devices to control the data transfers thereof according to said control program.

Claim 3

A numerical control system as defined in claim 1 wherein each of said devices includes signal means for indicating the readiness of the device to transfer data, each of said signal means being connected to the processor, said control program including separate subroutines for responding to the respective signal means to carry out the data transfers.

Claim 4

A numerical control system as defined in claim 2 wherein each of said signal means includes means for transferring to said processor an address identifying the device.

Claim 5

A numerical control system as defined in claim 2 including means for responding to the signal means to carry out the data transfers according to a predetermined order of priority.

Claim 6

A numerical control system as defined in claim 4 wherein said means for responding includes logic connected intermediate the signal means and the processor.

Claim 7

A numerical control system as defined in claim 1 wherein said means for reading a stored program is a punched-tape reader for reading coded characters in sequence.

Claim 8

A numerical control system as defined in claim 2 wherein one of said devices is a group of switches for inputting data to the processor, the system further including at least one additional data input means, said control program including a subroutine for transferring data from said data input means only when none of said separate subroutines is being executed.

Claim 9

A numerical control system as defined in claim 2 wherein the processor has input, output, and interrupt channels, each of said signal means including an interrupt signal generator connected to the interrupt channel.

Claim 10

A system as defined in claim 8 wherein the combination includes interrupt control means operatively associated with the interrupt channel for accepting interrupt signals from said signal means of said devices; means responsive to an interrupt signal to determine the address of the interrupting device, and means responsive to the device address for initiating an interrupt sErvice subroutine.

Claim 11

A system as defined in claim 9 wherein the interrupt control means includes logic means for disabling the interrupt channel during the execution of an interrupt service subroutine.

Claim 12

A system as defined in claim 10 wherein the logic means is at least partly external to the processor.

Claim 13

A system as defined in claim 10 wherein the logic means includes a bistable device, a gate connected directly in the interrupt channel, the bistable device being connected to the gate to render the gate conductive to interrupt signals when the bistable device is in one of the two possible conditions thereof.

Claim 14

A system as defined in claim 8 wherein the interrupt signal means includes OR logic means commonly connected to receive all of the interrupt signals from the data source devices to permit passage of any one such signal to the interrupt channel.

Claim 15

A system as defined in claim 13 including circuit means interconnected between the signal means for identifying the highest priority interrupting device upon interrogation by the processor.

Claim 16

A system as defined in claim 14 wherein each of the interrupt signal means includes a bistable device switchable from a first condition to a second condition in response to a data flow condition in the associated data source device, the circuit means including a plurality of coincidence gates individually associated with the signal means, and an priority signal line connected from the output channel through the coincidence gates in series from the highest priority device to the lowest priority device in order, the coincidence gates being rendered nonconductive in response to the transition of the associated bistable device from the first to the second condition whereby the priority signal passes only to the highest priority device having remained in the first condition.

Claim 17

A system as defined in claim 15 wherein the processor responds under the control program to the receipt of an interrupt signal from the tape reader to determine the presence of a parity error.

Claim 18

A system as defined in claim 8 wherein one of said devices is a clock for generating timing signals at a selected rate, the clock means being connected to the interrupt channel to generate an interrupt at said selected rate.

Claim 19

A system as defined in claim 8 including alarm means for indicating a failure of the processor to produce predetermined signals on the outpt channel within a predetermined fixed interval.

Claim 20

A system as defined in claim 8 wherein one of the devices is an interpolator for producing command pulses to the mechanism in accordance with part program data supplied thereto, a first counter of relatively small capacity connected to receive and count the pulses, and means for periodically and cumulatively transferring the contents of the first counter to a second relatively large capacity register, said register being maintained in the memory of the processor.

Claim 21

A system as defined in claim 8 including manual input means connected to the input channel for entering data into the processor memory.

Claim 22

A system as defined in claim 20 wherein the manual input means includes a plurality of switches, some of said switches being input data source devices having signal means connected to the interrupt channel.

Claim 23

A system as defined in claim 21 wherein some of said switches are position maintaining in character, and means controlled by the control program in the processor for scanning the switches for operative connection to the input channel.

Claim 24

A system as defined in claim 22 wherein the control program includes a plurality of interrupt service substantives peculiar to the scanned switches being at least approximately the lowest order of priority.

Claim 25

A system as defined in claim 21 wherein at least some of the switches are limit switches for monitoring displacement of the tool.

Claim 26

A numerical control system for a machine tool having a mechanism which effects controllable displacement along at leasT one tool axis comprising in combination: a part program reader for reading part program digital characters defining contiguous portions of a contoured tool path to be executed by said mechanism; an interpolator for producing digital command pulses to the mechanism in response to blocks of said characters; a plurality of switches having open and closed positions and normally residing in one of such positions; a programmable digital processor having input and output channels interconnecting the reader, interpolator, and switches for controlling the flow of data therebetween, and an interrupt line; said processor including a control program in memory; individual interrupt signal means connected to each of the reader and interpolator for producing interrupt signals in response to data flow conditions including the readiness to read a character and the need for a block, respectively; means connecting the signal means to the processor, means for identifying the signal from the signalling device of highest rank in a predetermined priority order, said means for identifying including a single signal line connected between said processor and said reader and interpolator, logic gates associated with the reader and interpolator, respectively, said signal line being connected through said gates according to said predetermined order, said signal means being connected to said logic gates to permit the signal on said line to propagate only as far as the highest priority interrupting device, means in said processor responsive to receipt of an interrupt signal from one of said individual interrupt signal means to generate an acknowledge signal, means associated with each of said reader and interpolator, respectively, and responsive to the combination of said single signal and said acknowledge signal to transfer a device address to said processor to identify the highest priority interrupting device; said processor having subroutines responsive to each of the interrupting devices to effect a flow of data toward the tool mechanism.

Claim 27

A numerical control system for a machine tool having a mechanism which effects controllable displacement along at leasT one tool axis comprising in combination: a part program reader for reading part program digital characters defining contiguous portions of a contoured tool path to be executed by said mechanism; an interpolator for producing digital command pulses to the mechanism in response to blocks of said characters; a plurality of switches having open and closed positions and normally residing in one of such positions; a programmable digital processor having input and output channels interconnecting the reader, interpolator, and switches for controlling the flow of data therebetween, and an interrupt line; said processor including a control program in memory; individual interrupt signal means connected to each of the reader and interpolator for producing interrupt signals in response to data flow conditions including the readiness to read a character and the need for a block, respectively; means connecting the signal means to the processor, means for identifying the signal from the signalling device of highest rank in a predetermined priority order, said means for identifying including a single signal line connected between said processor and said reader and interpolator, logic gates associated with the reader and interpolator, respectively, said signal line being connected through said gates according to said predetermined order, said signal means being connected to said logic gates to permit the signal on said line to propagate only as far as the highest priority interrupting device, means in said processor responsive to receipt of an interrupt signal from one of said individual interrupt signal means to generate an acknowledge signal, means associated with each of said reader and interpolator, respectively, and responsive to the combination of said single signal and said acknowledge signal to transfer a device address to said processor to identify the highest priority interrupting device; said processor having subroutines responsive to each of the interrupting devices to effect a flow of data toward the tool mechanism.

Claim 28

A system as defined in claim 25 wherein each of the subroutines includes the generation of a disable signal, and gate means between the signal means and the processor responsive to the disable signal to prevent the flow of interrupt signals.

Claim 29

A system as defined in claim 26 wherein each of the interrupt signal means includes a bistable device which changes state in response to a data flow condition, and means for resetting each such bistable device only after the interrupting device associated therewith has initiated the subroutine therefor whereby lower priority devices not serviced maintain the interrupt signal-producing state.

Claim 30

A system as defined in claim 27 including circuit means connected between the part program reader and the input channel for transferring an address peculiar to the reader to the processor, gate means in the circuit means, means for enabling the gate means when the processor receives an interrupt signal and, coincidently therewith, the bistable device of the reader changes state.

Claim 31

A system as defined in claim 28 including means for resetting the bistable device of the reader when the gate means is enabled.

Claim 32

A system as defined in claim 25 wherein each of the switches include first and second contacts, the first contacts being connected to the interrupt line, the second contacts being connected to the input channel through gate means, said means connecting the signal means to the processor being effective to enable the gate means.

Claim 33

A system as defined in claim 25 including means for displaying the position of the switches.

Claim 34

A system as defined in claim 31 wherein the switches are push buttons for entering numerical data into the processor.

Claim 35

A system as defined in claim 32 wherein all of the push buttons are connected to a single interrupt signal means.

Claim 36

A system as defined in claim 25 wherein the part program reader is a tape reader.

Claim 39

The method defined in claim 35 comprising the additional step of resetting an alarm signal timer after the execution of each service routine.

Claim 40

A numerical control system for directing a mechanism for controlling the displacement of a controlled quantity along at least one axis comprising: a part program source for holding in storage a segmented program defining the overall parameters of a contoured path to be traced by said quantity, a plurality of devices including an interpolator adapted for connection to and controlled by a programmable digital processor having a control program in memory for transferring segments of said part program toward the mechanism for direction of said controlled quantity along said axis, one of said devices including means for retrieving from said source said segments of the part program defining contiguous displacements of said controlled quantity the transfer of data between said devices being controlled by the control program.

Claim 41

A numerical control system for directing a mechanism for controlling the displacement of a controlled quantity along at least one axis comprising: a part program source for holding in storage a segmented program defining the overall parameters of a contoured path to be traced by said quantity, a plurality of devices including an interpolator adapted for connection to and controlled by a programmable digital processor having a control program in memory for transferring segments of said part program toward the mechanism for direction of said controlled quantity along said axis, one of said devices including means for retrieving from said source said segments of the part program defining contiguous displacements of said controlled quantity the transfer of data between said devices being controlled by the control program.