Abstract:
A personal computer incorporated in a numerical control device (CNC) has a function for emulating a CNC display circuit. This personal computer emulates a CNC display circuit and converts a transmitted display command A into a video signal for transmission to display means. The numerical control device (CNC) incorporating this personal computer need not to provide a display circuit for each of the CNC body and the personal computer, and, moreover, a switching circuit for selectively receiving the video signals from two display circuits and transmitting selected signal to the display means is not required either. Furthermore, the personal computer has a function for emulating a data input/output circuit of CNC. The personal computer inputs or outputs data transmitted from the CNC or data to be transmitted to the CNC, from or to a data input/output circuit in the personal computer to or from an external input/output device, through an input/output data RAM. Therefore, it is not necessary to provide data input/output circuits for both the CNC body and the personal computer.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a numerical control device, and more particularly, to a screen display and data input/output method for a numerical control device. 
     DESCRIPTION OF THE RELATED ART 
     Generally, a numerical control device comprises a control section and a drive section, and the control section can be divided further into a section for controlling data input operations, and a section for generating machine control information in real time on the basis of input information and transferring commands to the drive section. 
     Usually, the control section is provided with a dedicated computer and software for control purposes, and the drive section comprises a servo motor or main axis motor, or a servo amplifier for driving a motor of this kind. In order to carry out machining using a machine tool controlled by a numerical control device, in general, a processing program is previously created or input by the input operation control section in the control section of the numerical control device, and processing commands are output to the drive section in accordance with this processing program, thereby controlling the driving mechanism of the machine tool. 
     The aforementioned numerical control device is also provided with a display device, which displays various information, such as the input data, control status, etc., and is used in input operations and control. 
     FIG. 4 is a block circuit diagram for describing an outline of the display function of a conventional numerical control device. In FIG. 4, parts of the composition other than the display function of the numerical control device are omitted. In the diagram, a body (hereinafter, referred to as CNC body,)  1 , comprising a control section and a drive section of a numerical control device, is connected via a bus  3  to a display circuit (hereinafter, referred to as CNC display circuit)  5 , which drives a display device  4 . The CNC body  1  is also connected via the bus  3  to input means  1   a , such as a keyboard and a pointing device, such as a mouse and the like, and input data A is stored in a data RAM  1   c.    
     In performing the display operation in the numerical control device, bit map data or graphics commands (B 1 ) generated on the basis of the data stored in the aforementioned RAM  1   c  or the data in the CNC body  1  is transferred via the bus  3  to CNC display circuit  5 , which generates a video signal B 2  by means of analytical software stored in an internal RAM  5   b , and provides required display on the display device  4 . 
     Reference numeral  21  denotes a data input/output circuit comprising an interface conforming to standards such as RS 232 C, PCMCIA, or the like, and is designed for data input/output between the body  1  and an external CNC input/output device  22  for CNC. 
     By connecting a numerical control device of this kind to a personal computer which can easily be extended and adapted, the functions of an existing numerical control device can be modified or extended in accordance with the operator&#39;s needs or convenience. 
     FIG. 5 is a block diagram for describing an outline of a display function of a numerical control device incorporating a personal computer. In the composition shown in FIG. 5, a personal computer  2  is connected via a bus  3  to the numerical control device having the composition illustrated in FIG. 4 above, and both the CNC display circuit  5  and a display circuit  2   a  of the personal computer  2  are designed to be connectable to a common display device  4  by means of a switching circuit  6 . When the CNC body  1  is to provide a display, it does so by transmitting a video signal B 2  to the display device  4  by means of the CNC display circuit  5 . On the other hand, when the personal computer  2  is to provide a display, it does so by transmitting a video signal C to the display device  4  by means of a display circuit  2   a . In this method, a switching circuit  6  is provided among the CNC display circuit  5 , personal computer  2  and the display device  4  in order that data from both the CNC body and the personal computer can selectively be displayed using the common display device  4  by operating the switching circuit  6  for selecting either video signal B 2  or Video signal C, thereby transmitting one of the video signals to the display device  4 . The memory means  2   b  is for storing software for controlling the personal computer, and data input/output between the personal computer and an external input/output device  24  for the personal computer is made by means of a data input/output circuit  23  conforming to standards such as RS 232 C, PCMCIA or the like. 
     Therefore, with a conventional numerical control device incorporating a personal computer, it is not only necessary to provide a display circuit for both the CNC body and the personal computer but also necessary to provide a switching circuit for selecting the video signal by its source, that is, the two display circuits, to transfer the selected signal to the display device. Furthermore, in the case of the conventional numerical control device, for data input/output, a separate data input/output interface for the personal computer (data input/output circuit  23 ), and a separate CNC data input/output interface (data input/output circuit  21 ) are required. 
     SUMMARY OF THE INVENTION 
     In a numerical control device incorporating a personal computer, and a screen display and data input/output method for a numerical control device, it is an object of the present invention to conduct screen display and data input/output without using a CNC display circuit and a switching circuit. 
     In order to achieve the aforementioned object, the screen display and data input/output method according to the present invention comprise steps of: transferring display commands generated by a numerical control device to a personal computer incorporated in the numerical control device, emulating a display circuit function of the numerical control device to convert the display commands into a video signal and transmitting the converted video signal to display means, and displaying display contents from the numerical control device on a screen of the display means using the video signal. Further, it is preferable for the present invention to have an external input/output device connected to the computer, and comprise the steps of: transferring data from the numerical control device to the personal computer and, through which, outputting the data to the external input/output device, when the display contents from the numerical control device is displayed on a screen of the display means, and transferring numerical control data input from the external input/output device to the numerical control device. 
     Furthermore, in the numerical control device according to the present invention, a personal computer is connected via a bus to a numerical control device body, and a converting means for emulating a function for displaying display commands generated by the numerical control device body is added to the circuitry of the personal computer so that display command generated by the numerical control device body can be converted into a video signal by the converting means and displayed. 
     Preferably, the converting means comprises data storing means for storing display command, and conversion control means for converting display command into a video signal and controlling output thereof. 
     More preferably, the conversion control means comprises software storing means, the software storing means being designed for storing analytical software for analyzing and converting display command into a video signal, and drivers for controlling output of the video signal. 
     Even more preferably, the personal computer comprises data transfer means for transferring data between the personal computer and the numerical control device, and data input/output means for data input/output between the personal computer and the external input/output device. 
     According to the present invention, in a numerical control device incorporating a personal computer, it is possible to display on a screen the contents of display command generated by the numerical control device body, without providing a display circuit or switching circuit for the numerical control device body. 
     Furthermore, since it is not necessary to provide a data input/output circuit or interface for the numerical control device body in order to be connected to an external input/output device, the composition of the numerical control device can be simplified and thus manufacturing costs can be reduced. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a block diagram showing an outline of a numerical control device according to one mode of implementing the present invention, wherein a personal computer is incorporated; 
     FIG. 2 is a block diagram of a servo motor control system in a numerical control device to which an embodiment of the present invention can be applied; 
     FIG. 3 is a block diagram showing an outline of another embodiment of a numerical control device incorporating a personal computer according to the present invention; 
     FIG. 4 is a block diagram for describing an outline of a display function in a conventional numerical control device; and 
     FIG. 5 is a block diagram for describing an outline of a display function of a conventional numerical control device having composition wherein a personal computer is incorporated. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Firstly, a description is given of a servo motor control system in a numerical control device, to which an embodiment of the present invention can be applied, with reference to the schematic block diagram in FIG.  2 . The servo motor control system used here is virtually the same as a conventional control system, and is therefore only described in general terms here. 
     In FIG. 2,  10  is a CNC control section including a computer;  11  is a common RAM;  12  is a digital servo circuit including a processor (CPU), ROM and RAM and the like;  13  is a power amplifier, such as a transistor inverter or the like;  14  is an AC servo motor;  15  is an encoder for generating pulses as the AC servo motor  14  rotates; and  16  is a rotor position detecting device for detecting the rotor phase. 
     The CNC control section  10  and common RAM  11  form the control section CTR of the numerical control device; and the common RAM  11 , digital servo circuit  12 , power amplifier  13 , AC servo motor  14 , encoder  15 , and rotor position detecting device  16  form the drive section DRV of the numerical control device. Usually, the control section CTR is provided with a dedicated computer and software for control purposes, and the drive section DRV is provided with a servo motor or main axle motor, or a servo amplifier for driving such a motor. Generally, in carrying out machining by means of a machine tool controlled by the numerical control device, a machining program is previously created or input by the input operation control section of the control section CTR, and machining commands are output to the drive section DRV in accordance with this machining program, thereby controlling the driving mechanism of the machine tool. 
     A generally used CNC control section comprises a section for controlling data input operations (CNC display circuit), and a section for generating machine control information in real time on the basis of input information and transferring commands to the drive section, but the CNC control section  10  in the numerical control device incorporating a personal computer according to the present invention does not comprise a CNC display circuit, by performing the function of the CNC display circuit by emulation on the side of the personal computer. 
     Next, a mode for implementing a numerical control device incorporating a personal computer according to the present invention is described using the schematic block diagram in FIG.  1 . 
     In FIG. 1, the numerical control device incorporating a personal computer can be formed by a configuration wherein a CNC body  1  (numerical control device body) is connected to a personal computer  2  via a bus  3 . 
     The CNC body  1  comprises a control section CTR including at the least a CNC control section  10  and a common memory  11 , as illustrated in FIG. 2, and the drive section CTR comprises storing means  1   b  for storing software for controlling the CNC body, and storing means  1   c  for storing generated data. Here, the storing means  1   b  and  1   c  may be constituted either of the common RAM  11  or of a dedicated RAM. 
     The personal computer  2  may comprise a signal conversion means  20   a  added to a generally used personal computer. A personal computer  2  includes in its standard sections storing means for storing software for controlling the personal computer, and a display circuit  2   a . And the display contents from the personal computer  2  itself are generated by the display circuit  2   a , which is a standard section, in the form of a video signal C, and are then displayed by transmitting this video signal C to the display device  4 . 
     A personal computer incorporated into the numerical control device according to the present invention is provided with signal converting means  20   a  for emulating the display function of the CNC body  1 . This signal converting means  20   a  comprises data storing means  20   c  for receiving and storing display contents from the CNC body  1 , software storing means  20   b  for storing analytical software for analyzing data stored in the data storing means  20   c  and generating a video signal, and a driver (software) for controlling the output of the video signal and transmitting it to the display device  4 . The driver software can be formed using command designated by the user through the personal computer. 
     The display contents deriving from the CNC body  1  comprise, for example, bit map data, graphics command or the like, and the analytical software analyzes the bit map data and the digital data for the graphics commands to generate analogue video signal B 2 . The personal computer  2  generates a video signal B 2  corresponding to the display contents from the CNC body  1  using this analytical software, and it controls the output of the generated video signal B 2  using the driver. 
     Therefore, the personal computer  2  transfers the display contents from the personal computer to the display device  4  by means of the display circuit  2   a  in the form of a video signal C, and a screen showing these display contents is displayed, and, furthermore, it transfers the display contents from the CNC body to display device  4  by means of the appended signal converting means  20   a  in the form of a video signal B 2 , and a screen showing these display contents is displayed. 
     The selection regarding which of video signal B 2  or video signal C is output can be made by switching in the personal computer. Possible methods for switching video signal include a method of switching based on key input, or the like, at the personal computer, or a method whereby the personal computer monitors the data storing means  20   c  periodically and generates a video signal when it detects that display contents from the CNC body are stored in the data storing means  20   c , the display being switched from the personal computer display to the CNC body display in accordance with a display request, or the like. 
     A RAM, or the like, for example, may be used as aforesaid storing means. 
     Therefore, according to the mode for implementing the present invention illustrated in FIG. 1, it is possible to omit the CNC display circuit and the video signal switching circuit. Furthermore, even if the device composition omits the CNC display circuit, emulation can be made by means of analytical software in the personal computer, and the display contents are analyzed and converted into a video signal, so that similar operation to that performed by a CNC display circuit can be achieved. 
     Moreover, since the operator can determine commands for the driver as he or she wishes, the operation can be modified to suit the operator&#39;s method of application, without changing the CNC body. 
     Next, a further mode for implementing a numerical control device incorporating a personal computer according to the present invention is described with reference to the schematic block diagram in FIG.  3 . 
     The composition of the personal computer  2  required for omitting the CNC display circuit and video signal switching circuit, in other words, the composition of the signal converting means  20   a , data storing means  20   c , and software storing means  20   b , is similar to that in the mode of implementation illustrated in FIG.  1 . 
     The data RAM  1   d  in the CNC body  1  functions as a data input/output buffer between the CNC body  1  and an external input/output device. 
     The data RAM  25   c  in the personal computer  2  is a data input/output buffer between the personal computer  2  and an external input/output device, and it is connected to the microprocessor of the personal computer via an internal bus. The data input/output circuit  23  comprises an interface conforming to RS 232 C standards, PCMCIA standards, or the like, connected to the external input/output device  26 , and it is connected to the internal bus of the personal computer  2 . 
     Similarly to a conventional personal computer, the analytical software  25   b  has a function for successively reading data of a prescribed length from the data input/output circuit  23  by means of the microprocessor in the personal computer  2  and storing the data temporarily in the data RAM  25   c , when the data for personal computer is displayed on the screen of the display device  4 , and storing the contents of this data in a main memory of the personal computer  2  via the microprocessor of the personal computer  2  (when data from the external input/output device  26  is to be input to the personal computer  2 ), as well as a function for successively reading data of a prescribed length from the main memory of the personal computer  2  by means of the microprocessor in the personal computer  2  and storing the data temporarily in the data RAM  25   c  each time reading is carried out, and outputting the contents of the data to the data input/output circuit  23  by means of the microprocessor in the personal computer  2  (when data from the personal computer  2  is output to the external input/output device  24 ). Hereinafter, these functions are referred to as standard input/output functions. 
     Furthermore, the analytical software  25   b  in this mode of implementation has a function of successively reading data of a prescribed length from the data input/output circuit  23  by means of the microprocessor in the personal computer  2  and storing the data temporarily, when the data for the numerical control device is displayed on the screen of the display device  4 , and transferring the contents of this data, each time reading is carried out, to the data RAM  1   d  of the CNC body  1  through the bus and the microprocessor in the personal computer  2  (when data from the external input/output device  26  is input to the CNC body  1  via the personal computer  2 ) as well as a function for reading data from the data RAM  1   d  of the CNC body  1  by means of the microprocessor in the personal computer  2  and storing the data temporarily in the data RAM  25   c , and outputting the contents thereof to the data input/output circuit  23  via the microprocessor in the personal computer  2  (when data from the CNC body  1  is output to the external input/output device  26  via the personal computer  2 ). Hereinafter, these functions are referred to as remote input/output functions. 
     In brief, the analytical software  25   b  comprises a driver software providing standard input/output function and a driver software providing remote input/output function. When data for the numerical control device is displayed on the screen of the display device  4  by the input means  1   a , the driver software providing remote input/output function is selected to enable the data for the numerical control device to be input and output. Furthermore, when data for the personal computer is displayed on the screen of the display device  4 , the driver software providing the standard input/output functions is selected and data for the personal computer can be input and output. 
     Consequently, the CNC body  1  and external input/output device  26  can be connected indirectly through the personal computer  2 , and so, even when a data input/output circuit  21 , as illustrated in the conventional example in FIG. 5, and an RS 232 C- or PCMCIA-standard interface, or the like is not provided additionally in the CNC body  1 , data can be input and output between the CNC body  1  and the external input/output device  26 . Hence, by composing a CNC body  1  without comprising an input/output circuit  21  or an RS 232 - or PCMCIA-standard interface or the like, the composition of the CNC body  1  can be simplified, and, as a result, its manufacturing costs can be reduced.