GB2163927A

GB2163927A - Graphic display for a numerical control system

Info

Publication number: GB2163927A
Application number: GB08519136A
Authority: GB
Inventors: Joseph Edward Deklotz; Thomas Edward Manuel; David Arthur Palmer
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1984-08-31
Filing date: 1985-07-30
Publication date: 1986-03-05
Also published as: JPS6165315A; FR2569876A1; DE3530606A1; GB8519136D0

Abstract

The display of graphic "plot files" is added to the standard video display 18 of a computer numerical control system for-controlling the operation of a machine tool 10 in the performance of specified operations with respect to a workpiece. A set of graphic command sequences for generating a graphic display of data such as machine diagnostic aids, parts setup diagrams, machine setup diagrams is contained within a memory 21 storing graphic data files with predetermined graphic command sequences. The plot files are selected for display in three different ways, namely by: operator selection, part program selection, or machine control logic selection. Each file is transferred to the numerical control station 12 of the system where the command sequence are interpreted and the required graphic calls for displaying a predetermined graphic pattern of a plot file are generated by commands for displaying the graphic which are sent to the cathode ray tube 18 of the numerical control station 12. <IMAGE>

Description

SPECIFICATION Graphic display support for a numerical control system Cross reference to related applications This invention is related to the following U.S. and U.K. Patent Applications: U.S. Serial No. 415 041, entitled, "Customization Window For A Computer Numerical Control System", filed on 7th September 1982; U.K. Application No. 8519137 (Agents' Reference P/1671 (2512) entitled, "Graphics Display Generation Method For A Numerical Control System", filed in our name on the same date as this application, and U.K. Serial No. 8519135 (Agents' Reference P/1669(2510), entitled "Color Enhanced Display For A Numerical Control System", filed in our name on the same date as this application.

These related applications am all owned by the Applicants of the present invention and are intended to be incorporated herein by reference.

Background of the invention This invention relates generally to computer numerical control systems for machine tools and more particularly to graphic displays for such systems.

Numerical control systems for controlling machine tools in accordance with the execution of a digital computer are well known. Such systems control the machining operation in response to one or more part programs which are stored in a memory after having been loaded into the memory, for example, by punched tape. Upon demand, the part program directs the machine through a series of fabrication steps.

Where the machine includes a cutting tool, the relative motion between the workpiece and the cutting tool is normally along three mutually perpendicular axes to make a series of.straight line or circular cuts in accordance with the part program which dictates the cutting tool motion. Additionally, a computer numerical control (CNC) system may be adapted to control other functions such as tool changes, spindle speed, coolant flow, pallet selection and video graphics and message generation. The number and type of functions vary considerably depending upon the type of machine tool being controlled. In the past control has been performed by dedicated hard-wired circuits which operate in response to sensed conditions on the machine tool and to commands in the part program.More recently, however, the logic associated with machine tool control systems has been implemented in a computerized system by means of a set of stored programs, i.e., software, to provide the overall control. The software is tailored for a particular application but may be modified as required to meet the specific needs. The addition of programmable control to a numerical control system provides a number of advantages, the first and foremost is that it is only necessary to reprogram the control to enable it to interface with a particular machine. Additionally, it is relatively easier for the user to program because of the type of instruction set which is employed and the editing features which are available.A computerized numerical control may include two separate sets of software, namely, the "numerical control logic", termed the NC software, which is more or less fixed in content, and the "machine control logic", termed the MCL program, which is flexible and adaptable for customization to a particular machine tool. In the industry, customization is usually carried out by an original equipment manufacturer (OEM). The NC software controls part making, movement of axes, message display and other auxiliary functions while the MCL program primarily controls operation of the machine tool. In the above-mentioned U.S.Patent Application entitled, "Customization Window For A Numerical Control System", there is disclosed, moreover, a software interface, i.e., the customization window, comprised of a group of programs, input/output arrays, and status flags that link the NC software, the MCL program and the machine tool. In the related U.K. Patent Application, entitled, "Graphics Display Generation Method For A Numerical Control System", there is disclosed a method implemented in the customization MCL program for generating graphic displays of machine status information when a machine tool operator, for example, requests such a display. A graphic display is provided which is dynamically updated on a periodic basis. In the other related U.K.Patent Application, entitled, "color Enhanced Display For A Numerical Control System", there is disclosed the method and means for adding and enhancing color for the alpha-numeric and graphic display of a computer numerical control system.

Summary of the invention An object of the present invention is to provide an improvement in the methods by which information is displayed graphically on the display terminals used in conjunction with numerical control systems.

Briefly, the foregoing and other objects are achieved in accordance with integration of the display of graphic plot files into apparatus for displaying alpha-numeric and graphic information on a numerical control station cathode ray tube video monitor. Sets of graphic command or escape sequences for displaying graphic plot files are stored in a graphic data file storage which may be, for example, a mass memory. These files are selected, on demand, for display in one of three ways, namely, operator selection, part program selection and machine control logic selection. Once selected, the graphic sequences contained in the stored plot file are sent to the numerical control station where the escape sequences are interpreted and graphic primitives (routines for graphic symbols) are called for drawing a line, circle, an arc, etc.These are coupled to the display unit of the numerical control station where the selected plot file is written onto the screen of the cathode ray tube.

Brief description of the drawings While the present invention is defined in the claims annexed to and forming part of this specification, a better understanding can be had by reference to the following description when taken in conjunction with the accompanying drawings in which: Figure 1 is a simplified block diagram illustrative of a known computerized numerical control system and means associated therewith for displaying plot files; Figure 2 is a diagram broadly illustrative of the software included in the CNC system of Figure 1; Figure 3 is a block diagram further illustrative of the CNC system software shown in Figure 2; Figure 4 is a block diagram generally illustrative of the sequence of operations of the CNC software; Figure 5 is a block diagram generally illustrative of the preferred embodiment of the subject invention; and Figure 6 is a flow chart illustrative of the method by which plot files are displayed in accordance with the subject invention.

Detailed description of the preferred embodiment Referring now to Figure 1, shown thereat is a computer numerical control (CNC) system for controlling a machine tool 10. The CNC system is comprised of three major hardware components: the numerical control station 12, the machine control station 14 and the NC system rack 16. The computer that controls the system is located on a circuit board, not shown, housed in NC system rack 16. Such a configuration is illustrative of a Mark Century 2000 computer numerical control system of the General Electric Company. This -system is capable of storing entire computer programs and sets of information files, editing the programs and files, and calling them up in a desired sequence for carrying out a complete set of routines that perform a specific task on a machine tool such as a lathe or milling machine.Further, a separate piece of apparatus 15 can be connected to an off-line computer system (not shown), for graphically displaying data from files in the off-line computer relating to the machining process or the CNC.

One example of such apparatus is that available from Tektronix, Inc. as their 4014 graphic display terminal which includes a cathode ray tube display 17. The graphic display terminal 15 includes sets of graphic command sequences of a specific known type for generating displays of data such as machine diagnostic aids, part setup diagrams, machine setup diagrams, etc. Graphic displays are needed, for example, to expedite the setup procedure for a machine part run.

The numerical control station 12 includes display apparatus 18 having a cathode ray tube and a keyboard 20 including special function keys to input files, for example, into memory and thereafter command retrieval of file information for program execution. The machine control station 14 includes a set of manual controls and push buttons 22 which are utilized for machine oriented operator functions such as mode selection, offset access, jog, spindle speed, feed rate, etc.

The functions performed by the controller shown in Figure 1 are determined by internally stored software which is comprised of three separate sets of programs. Shown in Figure 2, these programs comprise the numerical control logic 24 (hereinafter referred to as the NC software), the MCL window 26, and the machine control logic 28 (hereinafter referred to as the MCL program). The NC software 24 controls the making of parts, the movement of machine axes, and the display of messages and graphics on the video monitor 18. The NC software comprises a fixed or permanent part of the CNC system. The MCL program 28, on the other hand, specifically controls operation of the machine tool and is comprised of many subprograms, in modular type sections called packages, which allow for user customization by the original equipment manufacturer (OEM).The MCL window 26 comprises a set of software, such as disclosed in the said related U.S. Patent Application Serial No. 415 041, that permits the MCL program 28 to communicate with the NC software 24 and provides access to the inputs and outputs of the machine tool 10.

As further shown in Figure 3, the MCL program 28 consists of two parts, the Fixed MCL 30 and the Customization MCL 32. The Customization MCL 32 contains all the machine tool programs for controlling operation of the machine tool 10 while using the MCL window 26 software to provide the necessary machine interface. It is the Customization MCL 32 that is tailored for a particular type of system operation and to customize the CNC to control a particular machine tool. The Fixed MCL 30, on the other hand, is a set of software whose basic function is to monitor and control the operator devices on the machine con trol station 14 (Figure 1) and normally is used as is for most applications. The MCL window 26 is comprised of a series of window procedures and functions 34, status flag arrays 36 and input and output arrays 38 which normally cannot be changed so that the integrity of the NC software cannot be compromised by any of the user programmable functions and procedures programmed into the MCL 28.

The NC software 24 is comprised of routines for controlling part making 40, axis movement 42 and operator displays 44, spindle motion, timers, math functions, and machine setup data. The machine setup data, or MSD, is a precisely formulated list of data that supplies the system with such specific machine tool characteristics as feedrates, canned cycles, part program commands, and in accordance with related Application entitled "Color Enhanced Display for a Numerical Control System", color assign ments six display modes of information displayed in both alpha-numeric and/or graphic form on the CRT apparatus 18.

When the system is powered up, the NC software 24 executes first, as shown in Figure 5, to repeatedly call the MCL program 28 for execution. Each resulting pass through the MCL program is called a sweep and involves calling both the Fixed MCL programs 30 and the Customization MCL programs 32. The time between each MCL sweep depends upon the current processing state of the system and what has happened to the inputs received by the CNC from the machine tool 10 through the MCL window 26. The sweep time within the CNC software is primarily on a demand basis. Whenever an input from the machine changes or whenever one of the flags from the MCL window 26 changes, a sweep of the MCL occurs. In addition, if a certain period of time has elapsed since the last MCL sweep, a new MCL sweep begins.This means that the MCL program runs at a present minimum rate but runs faster if the activity of the machine tool 10 is high.

Considering now the subject invention, what is accomplished thereby is an integration of the display of "plot files" directly into the CNC system so that they are displayed directly on the CRT 18 of the numerical control station as shown in Figure 5 and thereby eliminating the additional display apparatus shown by reference numeral 15 in Figure 1. Accordingly, a plurality of graphic plot files, consisting of sets of graphic escape sequences, are entered into a graphic data file storage apparatus 21. Storage 21 may be a memory, such as a bubble memory, adapted for mass data storage. Other types of graphic sequences such as REGIS and NAPLS may also be utilized.

The graphic escape sequences are simply encoded pointers, or keys, each one of which is associated with a graphic element which is desired to be created on the CRT 18. For example, the escape sequences may be ASCII sequences. In any case, each sequence corresponds to a graphic element such as an alphanumeric character. Further, however, an escape sequence may be associated with the execution of a graphic primitive such as those for drawing a line between points, drawing a circte, or an arc.

What is required, however, is that the graphic data file storage 21 be coupled to the CNC system in such a way that file selection can be made in any one of three different ways: (1) operator selection, (2) part program selection, or (3) MCL selection. For this purpose, access to the graphic data file storage 21 is shown in Figure 5 being from the numerical control station 12two that once selected, the graphic command sequences contained in the selected file are sent back to the numerical control station 12 where the escape sequences are interpreted and the required graphic picture signal generation is effected and displayed on the CRT of the video monitor 18.

In operation, with the operator selection mode, a plot file selection is entered through a keyboard input such as keyboard 20. The part program selection mode, by contrast, involves a cal from the NC software 24 to the graphic data file storage 21. The MCL selection involves a call from the MCL program 28 through the MCL window 26 to the graphic data file storage 21. In each case, however, the select data file, once retrieved from memory, is transferred to the NC software 24 in the numerical control station 12 where its contents are interpreted and calls are generated for appropriate graphic primitives such as a line, a circle, an arc, a square, etc., using the parameters passed, from which a CRT display is then provided.

Figure 6 discloses a flow chart which illustrates the graphic display generation process. The three plot file selection modes, 46, 48 or 50 can be selected, respectively, by the operator, a part program being run, or by way of a window call from the MCL program 28. In any case, each selection is followed by a retrieve command 52 to the graphic data file storage 21 (Figure 5) which transfers the plot file to the numerical control station 12 as evidenced by step 54. There the graphic command sequences are interpreted (step 56) to generate calls for specific graphic primitives required for the particular plot file graphic. The graphic primitives are simply preselected routines utilized to generate and transmit drawing commands to the CRT 18 as shown by step 60.Thereafter, the CRT displays the graphic patterns of the selected plot file in response to the drawing commands as shown by step 62. In summary, once a file containing graphic escape sequences is selected, the escape sequences are sent to the display unit of the NC station 12. There, each sequence is examined and the associated graphic primitive code is executed.

A graphics symbol is displayed as a result. There is a one-to-one correspondence between an escape sequence and a particular graphic primitive.

Attached Appendices I and II respectively include coded examples of the selection of graphics by: (1) the NC part program, and (2) the MCL program. For the example selected by the part program, at some point during the machining operation a screen display automatically is triggered by code in the part program. In this example, the messages "Put The Control Into Single Cycle And Test" and "Press Cycle Start For Each Setup Instruction" will appear. With each "Cycle Start" selected by the operator, a different file will be displayed. In this example, the files contain information on the part to be machined.

For the MCL example, alarm conditions such as low coolant trigger initiation of a screen display indicating the nature of the alarm. A file can then be called indicating graphically the exact location of the alarm condition.

For operator selection, the operator simply selects a display page on the CRT screen, which page includes a file index. The desired file is then selected for display. As an example, the operator may desire to display information on the setup data for a particular part to be machined.

Thus what has been shown and described is a means for integrating and displaying graphic plot files directly on the video display apparatus of a computer numerical control system for controlling a machine tool to enable the user of the system to display such data as machine diagnostic aids, parts setup diagrams, machine setup diagrams, etc.

While there has been shown and described what is considered to be the preferred embodiment of the invention, modifications thereto will readily occur to those skilled in the art. It is not desired, therefore, that the invention be limited to the specific implementation shown and described, but it is intended to cover all such modifications, alterations and changes which fall within the spirit and scope of the invention as defined in the appended claims.

APPENDIX I N0010 (ID,PROG,TA1010,Acceptance Test Program : MC) N0020 (DSP,2,10,PUT THE CONTROL INTO SINGLE CYCLE AND TEST) N0030 (DSP,4,10,PRESS CYCLE START FOR EACH SETUP INSTRUCTION) N0040 MO2 N0050 (PLOT,3DFOR5) N0060 (PLOT,3DPAR2) N0070 (PLOT,FIXTO1) N0080 (PLOT,FIXT02) N0090 (PLOT,INST03) N0110 (DSP,2,10,EXIT SINGLE MODE, ENTER AUTO AND TEST) N0120 (DSP,4,10,TO DRY RUN AND PLOT:) N0130 (DSP,6,12,1: SELECT THE GRAPHICS DISPLAY PAGE) N0140 (DSP,7,12,2: TERMINATE TOOL PATH PLOTTING) N0150 (DSP,8,12,3: SETUP NEW PLOT LIMITS IF REQUIRED) N0160 (DSP,9,12,4:SELECT TOOL PATH PLOTTING AND PRESS CYCLE START) N9997 (MSG, > > > End of program < < < ) N9998 M30 N9999 (END,PROG) APPENDIX II - IF RDIN(a1~PB) THEN -- LOW COOLANT CONDITION, DISPLAY GRAPHIC ERROR PLOT NUM SELECT( LOW COOL- ANT~DISPLAY ): MSG := 'COOLANT LEVEL LOW '; DISP RETURN := DISP~PAGE~ LINE(90,25,MSG); ELSIF RDIN(a2~PB) THEN -- TOOL ABSENT CONDITION, DISPLAY GRAPHIC ERROR PLOT.NUM SELECTf TOOL AB- SENT~DISPLAY); MSG = 'TOOL ABSENT'; DISP RETURN := DISK PAGE LINE(90,25,MSG); ELSIF RDIN(a3~PB) THEN -- PALLET NOT AT LOAD POINT, DISPLAY GRAPHIC ERROR PLOT NUM SELECT( PALLET~ LOAD~DISPLAY ); MSG :='PALLET NOT AT LOAD POSITION '; DISP~RETURN : := DISP~PAGE~LINE (90,25,MSG); END IF;

Claims

1. A method for displaying plot files on display means of a computer numerical control system controlling the operation of a machining system, comprising the steps of: storing at least one set of graphic command sequences of a plot file in a memory; selecting said plot file graphic command sequences for display; retrieving said graphic command sequences from said memory; transferring said graphic command sequences to means could to said display means for interpreting said command sequences; interpreting said graphic command sequences and providing graphic generation signals for said display means; and coupling said -graphic generation signals to said display means, whereby a plot file display is disclosed to the user of such data as machine diagnostic aids, part setup diagrams and machine setup diagrams.

2. The method of claim 1 and wherein said step of storing further comprises the step of storing a plurality of sets of plot file graphic command sequences, and wherein said step of selecting comprises selecting one of said sets of plot file graphic command sequences.

3. The method of claim 2 and wherein said step of providing graphic generation signals further comprises the steps of calling primitive graphic procedures for generating predetermined graphic primitive command signals and thereafter transmitting said command signals to said display means.

4. The method of claim 3 and wherein said display means comprises video type display apparatus included in a numerical control station of said computer numerical control system.

5. The method of claim 4 nd wherein said display apparatus includes a cathode ray tube which is responsive to said command signals for generating said display of a plot file.

6. The method of claim 2 and any claim appendant thereto wherein said step of selecting comprises the step of an operator selecting one of said sets of plot file graphic command sequences.

7. The method of claim 6 wherein said operator selecting step includes selecting a plot file at said numerical control station.

8. The method of any of claims 2 to 5 wherein said step of selecting comprises the step of selecting one of said sets of plot file graphic command sequences by way of a part program being executed in said computer numerical control system.

9. The method of any of claims 2 to 5 wherein said step of selecting comprises the step of selecting one of said sets of plot file graphic command sequences by way of a subprogram of a machine control logic program being executed in said computer numerical control system.

10. The method of claim 9 and wherein said sub-program comprises a window call from said machine control logic program to the numerical control logic software through a window interface.

11. The method of claim 1 and wherein said step of selecting includes selecting by an operator, selecting by the running of a part program, or selecting by execution a sub-program of a machine control logic program.

12. A computer numerical control system for controlling the operation of a machining system, comprising: display means integral with said system for providing a visual display of system related data; means for storing at least one plot file comprised of a set of graphic command sequences of a predetermined type; means for providing selection and retrieval of said plot file from said storing means; means for interpreting graphic command sequences of said predetermined type and generating therefrom graphic generation signals; means for transferring said set of graphic command sequences of said at least one plot file to said means for interpreting and generating; and means for transmitting said graphic generation signals to said display means whereby a plot file is displayed to the user of such data as machine diagnostic aids, part setup diagrams and machine setup diagrams.

13. The system as defined by claim 12 wherein said display means comprises video type display means.

14. The system as defined by claim 12 wherein said system includes at least one control station and wherein said display means comprises viewing apparatus located on said one control station.

15. The system as defined by claim 14 wherein said viewing apparatus includes a video type monitor.

16. The system as defined by claim 15 wherein said monitor includes a cathode ray tube and wherein said graphic generation signals comprise signals for drawing a plot file on said cathode ray tube.

17. The system as defined by claim 16 wherein said system includes a numerical control station and a machine control station and wherein the first recited control station comprises the numerical control station.

18. The system as defined by claim 12 wherein said storing means comprises a memory for storing a plurality of plot files.

19. The system as defined by claim 12 wherein said selection means comprises operator selection means.

20. The system as defined by claim 12 wherein said selection means comprises a call from a part program being executed.

21. The system as defined by claim 12 wherein said selection means comprises a call from a subprogram of a machine control logic program being executed.

22. The system as defined by claim 12 wherein said system includes a numerical control station and a machine control station and wherein said system operates in accordance with a plurality of stored computer programs including a first set of programs implementing the numerical control logic and a second set of programs implementing the machine control logic and wherein said selection and retrieval means selectiveiy includes operator selection means on said numerical control station, a display call from a part program in said first set of programs, or a display call from a subprogram of said second set of programs.

23. A method according to claim 1 substantially as herein described with reference to and as shown in the accompanying drawings.

24. A system according to claim 12 substantially as herein described with reference to and as shown in the accompanying drawings.