JP5580180B2 - Display system for control devices that can be connected to multiple displays - Google Patents

Description

  The present invention relates to a display system for a control device to which a plurality of displays can be connected.

  In a control device for controlling a large machine or a transfer line, there is a configuration in which a plurality of indicators are installed for the purpose of monitoring and operating from a plurality of remote locations.

  In addition, there is a desire to refer to a screen displayed on a display device arranged on the machine tool for maintenance work at a place away from the factory where the machine tool controlled by the control device is installed.

  As a display connected to a control device, Patent Literature 1 discloses a display technique for emulating and displaying a display command related to display generated by a control device with a personal computer. This display device is suitable as a display device for connection to the control device because it is not necessary to provide a new display circuit or switching circuit in the control device.

JP-A-10-171516 Japanese Patent Laid-Open No. 3-188505 Japanese Patent No. 2666925 Japanese Patent Publication No. 7-109545 JP-A-9-146497 JP 2000-250502 A Japanese translation of PCT publication No. 2002-525684 JP-A-9-91228

As means for connecting the control device and the plurality of indicators, there are techniques disclosed in Patent Documents 2 to 8 described in the column of the prior art document.
Patent Document 2 discloses a technique for outputting a display signal for each display (see FIG. 12). In this technique, the control device needs to output display signals for a plurality of devices. If screens are displayed simultaneously on a plurality of display devices, the load on the screen display processing of the control device increases in proportion to the number of display devices to be connected, so that the number of display devices that can be connected is limited. Moreover, the power supply of arbitrary displays cannot be cut | disconnected among several displays.

  Patent Document 3 discloses a technique of switching and using a plurality of displays with a selective connection circuit (see FIG. 13). In this technique, since the control device only needs to perform screen display processing for one display device, the load on the control device does not increase, but screen display cannot be performed simultaneously on a plurality of display devices. For this reason, the screen display information of the control device is shared at the same time between the on-site operator, the maintenance staff in the maintenance department at a remote location, and the mechanical engineer at another location. Therefore, the display technique disclosed in Patent Document 3 cannot be used for the purpose of shortening the time required for the recovery work of the machine in which the trouble has occurred.

  Patent Document 4 discloses a technique in which when a plurality of displays are connected to a control device, the control device transmits screen data to all the displays. However, this technology requires screen data communication processing (flow control, retransmission processing when a communication error occurs, etc.) for each display, and thus increases the load on the control device. Moreover, it is necessary to add a communication buffer resource (RAM) for each display unit. Therefore, there is a problem in that the cost of adding a high-speed circuit and RAM for communication processing increases in the control device.

  Patent Documents 5 to 7 disclose techniques for outputting a video signal to a specific display device to which a control device is connected. The techniques disclosed in these patent documents require a dedicated display circuit and cannot be applied to a display that emulates and displays a display command on a personal computer as in Patent Document 1.

  Patent Document 8 discloses a technique for acquiring a bitmap image of a screen of a control device on the display side and displaying it on its own display. Even the technique disclosed in this patent document cannot be applied to a display that emulates and displays a display command with a personal computer, as in patent document 1. Further, with this technique, the size of the bitmap information to be transferred becomes enormous, and there is a problem in the display speed on the display side.

  As a means for connecting a plurality of displays to a single personal computer, there is a technique of configuring a network in which a personal computer and a plurality of displays are connected by a cable for video signals, and simultaneously displaying the same screen. However, in this technique, each display unit unilaterally receives and displays a video signal, so that the display unit disclosed in Patent Document 1 emulates a display command related to the display generated by the control device on the display side. It cannot be used as a display for connecting multiple devices.

  Further, in the technology for receiving and displaying the video signal as described above, since the display device cannot specify the control device to be displayed, on a network composed of a plurality of control devices and a plurality of display devices, Each display unit cannot specify a control device to be connected. Further, a separate key input network is required for the control device to receive key input from the keyboard connected to the display.

  Accordingly, an object of the present invention is to provide a control device capable of connecting a plurality of displays without increasing the processing load of the control device and without increasing the cost of the control device and the display in view of the above-described problems of the prior art. Is to provide a display system.

In the invention according to claim 1 of the present application, at least one control device is connected to a network, and a plurality of display devices that receive and process a display command related to display generated by the control device and display the screen are connected. In the display system, the control device includes means for permitting connection to a display that is initially requested for connection, network address storage means for storing the network address of the display that is initially requested for connection, Means for transmitting a display command to a display device that has requested connection, and when there is a connection request from another display device, the stored network address is notified to the other display device and the other display device. Network address storage means for storing the network address of the device, and the display device transmits means for transmitting a connection request to the control device to be connected, and the control device. Means for connecting to the control device and receiving a display command when the connection is permitted from the control device, and when the network address is notified from the control device when the connection is not permitted, the display is connected to the display of the notified network address. Means for receiving the command, means for processing the received display command to display the screen, and means for transmitting the received display command to the display device having the connection request when there is a connection request from another display device A display system characterized by comprising:
In the invention according to claim 2, when the power supply of an arbitrary display device is cut off, the display device that has made a connection request immediately before the display device from which the power supply was cut off connects its own network address to the previous one. A display unit that sends a request to the control device, and a display unit that requests connection after the display device that has been turned off includes a unit that issues a connection request to the control device. The display system according to claim 1.
According to a third aspect of the present invention, in the display system according to the second aspect, the network address storage means stores the order of the display devices requested to be connected and the network address.
According to a fourth aspect of the present invention, when the power supply of an arbitrary display device is cut off, the control device turns off the power supply to the display device that has issued a connection request after the display device that has been turned off. Means for transmitting the network address of the display device that issued the connection request immediately before the display device, and the display device notified of the network address makes a connection request to the display device of the notified network address. The display system according to claim 1 , further comprising: means.
The invention according to claim 5 is the display system according to any one of claims 1 to 4 , wherein the display unit includes means for changing a network address of a control device to be connected.
According to a sixth aspect of the present invention, the display device has key input means, and the information input by the key input device is transmitted to the display device or the control device that issued the connection request one time before connecting. The display system according to claim 1, further comprising: a transmission unit configured to perform transmission.

  According to the present invention, it is possible to provide a display system for a control device in which a plurality of display devices can be connected without increasing the processing load of the control device and without increasing the costs of the control device and the display device. In the prior art, the control device specifies the display. However, in the present invention, since the control device to be connected can be specified on the display side, when there are a plurality of control devices on the network, the display side It is possible to display the screen of any control device simply by changing the control device at the connection destination. For maintenance of the control device, if one display device is prepared at any location connected to the network, a plurality of remote control devices can be displayed. Maintenance of the control device can be performed.

It is a figure explaining the 1st Embodiment of this invention. It is a figure explaining the 2nd Embodiment of this invention. It is a figure explaining the 3rd Embodiment of this invention. It is a block diagram explaining the display apparatus for multiple connections (when connecting a control apparatus and a multiple connection display apparatus). It is a block diagram explaining the display apparatus for multiple connections (when connecting multiple connection display apparatuses). It is a flowchart explaining the process of a control apparatus. It is a flowchart explaining management of the multiple connection display apparatus in a control apparatus. It is a flowchart explaining the server process for control apparatuses in a control apparatus. It is a flowchart explaining the process of a multi-connection display apparatus. It is a flowchart explaining a client connection multiple connection display apparatus management. It is a flowchart explaining the server process for multiple connection display apparatuses. It is a figure explaining the prior art which connects a control apparatus and a some indicator. It is a figure explaining the prior art which connects a control apparatus and a some indicator, and switches and uses the said some indicator.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The server in the drawing refers to a process (function) in which a control device or a multi-connection display device that has received a connection request transmits (provides) a display instruction for screen display, and is transmitted (provided). The processing (function) that receives a display command and displays it on the screen is called a client.
The present invention uses, for example, a network represented by Ethernet (registered trademark), and has one or a plurality of control devices 200 and one or more having individual connection addresses (hereinafter referred to as “network addresses”). A plurality of multi-connection display devices 100 are connected. In FIG. 1, one numerical control device 200, the first to N + 1th multiple connection display devices 100 are connected on the network.
The control device 200 is, for example, a numerical control device that controls a machine tool or a control device that controls a machine such as a robot, and a conventionally known device can be used. As described above, each multi-connection display device 100 has a unique network address. Similarly, each control device 200 has a unique network address.
1, the multi-connection display device 1 means the first multi-connection display device 100, the multi-connection display device 2 means the second multi-connection display device 100,... The second multi-connection display device 100 is meant. The first to N + 1th multi-connection display devices 100 will be described later with reference to FIGS.

An embodiment of a display system of the present invention to which a plurality of multi-connection display devices 100 are connected will be described with reference to FIG.
<First Embodiment>
(1) The first multi-connection display device 100 issues a connection request to the control device 200 to be connected from among the plurality of control devices 200. In FIG. 1, only the connected control device 200 is illustrated. The control device 200 permits the connection as the first multi-connection display device 100 with respect to the multi-connection display device that first requested the connection. Thereafter, the control device 200 transmits a screen display command to the first multi-connection display device 100, and the first multi-connection display device 100 receives the screen display command from the control device 200 and performs screen display. Then, the first multi-connection display device 100 notifies the control device 200 of its own network address in order to make the control device 200 recognize that it is the terminal multi-connection display device 100. Store in a memory (not shown).
In FIG. 1, the own network address indicating the terminal multi-connection display device 100 is described as the terminal multi-connection display device address.

(2) Next, when the multi-connection display device illustrated as the second multi-connection display device 100 tries to connect to the same control device 200 to which the first multi-connection display device 100 is connected, control is performed. The device 200 notifies the second multi-connection display device 100 of the network address of the first multi-connection display device 100 that is the terminal multi-connection display device at the present time. The second multi-connection display device 100 is connected to the first multi-connection display device 100 that has acquired the network address, receives a screen display command from the first multi-connection display device 100, and receives the second multi-connection display device. A screen is displayed on a display (see 120 in FIG. 4) connected to the apparatus 100.
The second multi-connection display device 100 causes the numerical control device 200 to recognize itself via the first multi-connection display device 100 in order to make the numerical control device 200 recognize that it has become the terminal multi-connection display device 100. And the control device 200 stores it in a memory (not shown).

(3) Similarly, when the Nth multi-connection display device 100 tries to connect to the same numerical control device 200 as the first multi-connection display device 100, the numerical control device 200 stores the terminal multi-connection display device stored therein. The network address of the (N-1) th multi-connection display device 100 is notified to the N-th multi-connection display device 100.
The Nth multiple connection display device 100 is connected to the (N-1) th multiple connection display device 100, receives an image display command from the (N-1) th multiple connection display device 100, and receives the Nth multiple connection display device. A screen is displayed on a display device connected to 100.
Then, like the first and second multi-connection display devices 100, the N-th multi-connection display device 100 now indicates that it has become the terminal multi-connection display device 100, the N-1th, The N-2th,... Multi-connection display device 100 is sequentially notified, and finally the network address of the Nth multi-connection display device 100 is stored in the control device 200.

(4) By repeating this process between the control device 200 and the multi-connection display device 100, an arbitrary number of multi-connection display devices 100 can be connected to the control device 200.

In this way, the control device 200 transmits the screen display command to the first multi-connection display device 100 without increasing the load of the image display processing, and thus the N-th multi-connection display device 100. In response to a connection request from, the same screen can be displayed on the display of the multiple connection display devices 100 on the network only by notifying the network address of the multiple connection display device 100 as the termination.
As a result, even when the multi-connection display device 100 is connected to a plurality of networks, the control device 200 can distribute the load related to screen display to each multi-connection display device 100 connected to the network. The real-time processing such as machine control and signal control of a machine tool or the like, which is the original role of the control device 200, is not affected.

  Further, when a key input operation is performed on any of the multiple connection display devices 100 on the display system described above, the key input operation is performed on the control device 200 by passing information in the direction opposite to the transmission / reception of the screen display command. Notification is made possible, and a key input operation from any multi-connection display device 100 is made possible. For this reason, it becomes possible to operate the control device 200 to be operated from a remote place when maintenance of the machine or trouble occurs, and it is possible to shorten the time for maintenance work and recovery work.

Next, in the display system described above, a case where the power supply of an arbitrary multi-connection display device 100 is cut will be described as a second embodiment of the present invention with reference to FIG.
<Second Embodiment>
(1) When the power supply of the second multi-connection display device 100 is disconnected from the display system described in the first embodiment, the first multi-connection display device disconnected from the second multi-connection display device 100 100 informs the control device 200 of its own network address that it has become the terminal multi-connection display device 100.
(2) Next, the third multi-connection display device 100 disconnected from the second multi-connection display device 100 requests the control device 200 to reconnect.
(3) The control device 200 notifies the third multi-connection display device 100 of the network address of the first multi-connection display device 100 that is the terminal multi-connection display device 100.
(4) The third multi-connection display device 100 is connected to the first multi-connection display device 100 notified from the control device 200, and is terminated on the display system stored in the third multi-connection display device 100. The network system of the multi-connection display device 100 is notified to the control device 200 through the first multi-connection display device 100, thereby reconstructing the display system. In FIG. 2, the third multi-connection display device 100 stores the network address of the N-th multi-connection display device 100 as the network address of the terminal multi-connection display device 100.

As a result, it is possible to turn off the power of any multiple connection display device 100 on the network without stopping the machine.
To generalize the above-described matters, when the power of the Nth multi-connection display device 100 is cut off, the N-1th multi-connection display device 100 disconnected from the Nth multi-connection display device 100 is: Sequentially notifies the N-2th, N-3th,..., Multiple connection display devices 100 that the terminal device has become the terminal multiple connection display device 100, and is finally transmitted to the control device 200 to be transmitted to the control device. It is stored in 200 memories.

  Next, when the (N + 1) th multi-connection display device 100 disconnected from the N-th multi-connection display device 100 makes a reconnection request to the control device 200, the N−1th multi-connection display that is the terminal end is displayed. The network address of the device 100 is returned to the (N + 1) th multiple connection display device 100, and the (N + 1) th multiple connection display device 100 reconnects to the (N-1) th multiple connection display device 100.

  Thereafter, the network address of the terminal multi-connection display device 100 (for example, the M-th display) on the display system stored in the N + 1-th multi-connection display device 100 is changed from N + 1 to N−1. A plurality of control devices 100 are sequentially notified, and finally the control device 200 is notified that the Mth display device is a terminal display device, and the display system is reconstructed.

  Alternatively, the control device 200, for the N + 1th multi-connection display device 100 disconnected from the N-th display, has the network address of the N−1th multi-connection display device 100 that has become the terminal multi-connection display device 100. May be connected to the (N-1) th multi-connection display device 100 to reconstruct the display system.

  Furthermore, each multi-connection display device 100 has means for changing the network address of the control device 200 to be connected, and can be reconnected to any control device 200 even when there are a plurality of control devices 200 on the network. become. At that time, the disconnected display system is automatically reconfigured by the above-described display system restructuring means.

Next, in the display system described above, another embodiment in which the power source of an arbitrary multi-connection display device 100 is turned off will be described as a third embodiment with reference to FIG.
<Third Embodiment>
(1) When the power supply of the second multi-connection display device 100 is disconnected from the display system on the network, the first multi-connection display device 100 disconnected from the second multi-connection display device 100 itself The control device 200 is notified that it has become the terminal multi-connection display device 100.
(2) Next, the control device 200 that has been notified that the terminal multi-connection display device 100 has been changed has the third multi-connection display device 100 disconnected, and the second multi-connection display device 100 is disconnected. The second multi-connection display device 100 is notified that it becomes the terminal multi-connection display device 100.
(3) The third multi-connection display device 100 is connected to the first multi-connection display device 100 notified from the control device 200, and the display system is reconstructed.
As a result, it is possible to turn off the power of any multiple connection display device 100 on the network without stopping the machine.
According to the above-described embodiment of the present invention, the present invention can be applied to a control device installed in a factory in a remote place such as many machine configurations or overseas via a multi-connection display device installed in a production management building or a maintenance management building. Display and operation can be easily performed.

Next, the multi-connection display device 100 used in the embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram illustrating a multi-connection display device.
A processor (CPU) 101 is a processor that controls the multiple connection display device 100 as a whole, reads a system program stored in the memory 102 via the bus 106, and in accordance with this system program, displays the multiple connection display device 100. Overall control. The memory 102 includes an area for storing temporary calculation data, display commands, and the like. The processor (CPU) 101 is also connected to a display controller 103, a keyboard controller 104, and a communication controller 105 that send screen data to the display device 120 via the bus 106. The display device 120 is a liquid crystal display device or the like, and is controlled by the display controller 103. The keyboard 121 is controlled by the keyboard controller 104. The communication controller 105 has a client function and a server function. A control device 200 having a server function as shown in FIG. 4 or a multi-connection display device 100 having a server function as shown in FIG. 5 is connected to the client function of the communication controller 105. A multi-connection display device 100 having a client function is connected to the server function of the communication controller 105.
In the invention described in the claims of the present application, the “display device” is used as a concept including the multi-connection display device 100, the display device 120 connected thereto, and the keyboard 121.

Next, processing of each unit of the display system will be described with reference to flowcharts shown in FIGS.
FIG. 6 is a flowchart for explaining processing of the control device.
[Step ST01] A management process for a multi-connection display device is executed. Specifically, the process shown in FIG. 7 is executed.
[Step ST02] The control server server process is executed. Specifically, the process shown in FIG. 8 is executed.
Step ST01 and step ST02 are repeated.

FIG. 7 is a flowchart illustrating management of a multi-connection display device in the control device. In the process of this flowchart, a flag (server connection multi-connection display device flag FA) indicating whether or not there is a multi-connection display device connected to a control device having a server function is used.
[Step SA01] It is determined whether or not there is a new connection request from the multi-connection display device to the control device having the server function. If there is a connection request, the process proceeds to Step SA02, and the connection request is received. If not, the process ends. In other words, this is a step that means that the display system monitors whether or not there is a multi-connection display device newly connected to the display system.
[Step SA02] It is determined whether or not the server connection multi-connection display device flag FA is ON. If ON (YES), the process proceeds to Step SA03. If OFF (NO), Step SA05 is performed. Migrate to
If the flag FA is on, it means that there is already a multi-connection display device connected to the control device. If the flag FA is off, it means that there is no multi-connection display device connected to the control device.
[Step SA03] The network address of the multi-connection display device that is currently terminated is returned to the multi-connection display device that has requested connection (in other words, the multi-connection display device that has made a connection request to the control device). Move to SA04. That is, the termination multiple connection display device address allocated to the termination multiple connection display device is returned to the multiple connection display device that requested the connection from the control device, and the process proceeds to step SA04. (Transmission processing to step SD03 in FIG. 10)
[Step SA04] The network address of the multi-connection display device that has made the connection request is stored in the memory of the control device as the multi-connection display device that is the terminal. That is, the network address of the multi-connection display device newly requested for connection to the display system is stored in the memory of the control device as the network address of the terminal multi-connection display device. As a result, the multi-connection display device is recognized by the control device as a multi-connection display device which is a terminal.
When two or more multi-connection display devices are connected to one control device, the network addresses of the multi-connection display devices other than the multi-connection display device that is the terminal are also stored in the memory of the control device without being erased. .
[Step SA05] The server connection multiple connection display device flag FA is turned on. That is, since there is a multi-connection display device that is newly connected to the control device, the server connection multi-connection display device flag FA that is off is turned on.
[Step SA06] The network address of the multi-connection display device that requested the connection is stored in the memory. That is, it receives the network address of the multi-connection display device for which the connection request is made for the first time from the control device, and stores it in the memory as the network address of the terminal multi-connection display device. Thereby, the multi-connection display device is recognized by the control device as a multi-connection display device which is the end point.
[Step SA07] Communication is started with the connection-requested multi-connection display device (in other words, the multi-connection display device that has made a connection request to the control device), and the process ends.

FIG. 8 is a flowchart illustrating the control server server process.
[Step SB01] It is determined whether or not the server connection multi-connection display device flag FA is on. If it is on, the process proceeds to step SB02. If it is off, the process is terminated. Here, the fact that the flag FA is OFF indicates a state in which no multi-connection display device is connected to the control device.
[Step SB02] It is determined whether or not the server-connected multi-connection display device is in a normal communication state. If it is normal, the process proceeds to Step SB03, and if not normal, the process proceeds to Step SB06. Here, it is determined whether or not the communication state between the control device 200 and the first multi-connection display device 100 is normal.
[Step SB03] It is determined whether key input information is received from the server-connected multiple-connection display device. If key input information is received, the process proceeds to step SB04. If no key input information is received, step SB05 is performed. Migrate to
[Step SB04] Based on the received key input information, a key operation is executed in the control device. This key input information is transmitted by operating a keyboard on any one of the multiple connection display devices connected to the display system. (Received from step SE05 in FIG. 11)
[Step SB05] A display command is transmitted to the server-connected multiple-connection display device, and the process ends. (Send to step SD05 in FIG. 10)
[Step SB06] The server connection / multiple connection display device flag FA is turned off, and the process ends.

FIG. 9 is a flowchart for explaining processing of the multi-connection display device.
[Step SC01] A desired control device is selected on the display screen of the multi-connection display device. For example, a control device can be selected by reading a network address of a control device to be connected that is set in advance in a multi-connection display device connected to the network of the display system.
[Step SC02] It is determined whether or not the screen display is to be terminated. If it is terminated, the process proceeds to Step SC03, and if it is not terminated, the process proceeds to Step SC04.
[Step SC03] Exit from the screen display of the control device. For example, by turning off the power of the multi-connection display device, the screen display of the control device is removed.
[Step SC04] The multi-connection display device management is executed. Specifically, the process of FIG. 7 is executed.
[Step SC05] Client connection multiple connection display device management is executed. Specifically, the process of FIG. 10 is executed.
[Step SC06] The multi-connection display device server process is executed, and the process returns to Step SC02. Specifically, the process of FIG. 11 is executed.

FIG. 10 is a flowchart for explaining client connection display management. A flag indicating whether or not there is a multi-connection display device connected as a client (client connection multi-connection display device flag FB) is used.
[Step SD01] It is determined whether or not the client connection multiple connection display device flag FB is on. If it is on, the process proceeds to step SD07. If it is off, the process proceeds to step SD02.
[Step SD02] Connect to a desired control device. Here, the desired control device is the control device selected in step SC01 in FIG.
[Step SD03] Connect to the multi-connection display device using the network address representing the returned multi-connection display device. (Receiving the transmission by the process of step SA03)
[Step SD04] The client connection multiple connection display device flag FB is turned on.
[Step SD05] The address of the multi-connection display device that is the terminal is set as its own network address.
[Step SD06] The network address of the multi-connection display device that is the terminal is transferred to the previous multi-connection display device or control device, and the process is terminated. (SA04 in FIG. 7 or transmission to step SE07 in FIG. 11 of the previous multi-connection display device)
[Step SD07] A display command is received from the client-connected multi-connection display device, the screen is displayed, and the process is terminated. (Received from step SB04 in FIG. 8 and step SE03 in FIG. 11)

FIG. 11 is a flowchart illustrating server processing for a multi-connection display device.
[Step SE01] It is determined whether or not the server connection multiple connection display device flag FA is on. If it is on, the process proceeds to step SE02. If it is off, the process is terminated.
[Step SE02] It is determined whether or not the server-connected multi-connection display device is in a normal communication state. If it is in a normal communication state, the process proceeds to Step SE03, and if not, the process proceeds to Step SE08.
[Step SE03] The display command is transferred to the server-connected multi-connection display device. (Send to step SD05 in FIG. 10)
[Step SE04] It is determined whether or not key input information from the server-connected multiple-connection display device has been received. If key input information is received, the process proceeds to step SE05, and if key input information has not been received. Control goes to step SB06.
[Step SE05] The received key input information is transferred to the previous multiple-connection display device or control device. (Send to step SB03 in FIG. 8 or step SE05 in FIG. 11 of the previous multi-connection display device)
[Step SE06] For the control device having the server function, it is determined whether the network address of the newly connected multi-connection display device is received. If the network address is received, the process proceeds to Step SE07. If there is no reception, the process ends.
[Step SE07] The network address of the multi-connection display device serving as the terminal is stored in the memory. That is, the network address of the multi-connection display device newly connected to the display system is received and stored in the memory as the network address of the terminal multi-connection display device. As a result, the multi-connection display device is recognized by the control device as a multi-connection display device which is a terminal.
[Step SE08] The server connection multiple connection display device flag FA is turned off, and the process proceeds to Step SE09.
[Step SE09] The address of the multi-connection display device that is the terminal is set as its own network address.
[Step SE10] The network address of the multi-connection display device that is the terminal is transferred to the previous multi-connection display device or control device, and the process is terminated. (SA04 in FIG. 7 or transmission to step SE07 in FIG. 11 of the previous multi-connection display device)

100 Multi-connection display device 101 CPU
102 Memory 103 Display Controller 104 Keyboard Controller 105 Communication Controller 106 Bus 120 Display 121 Keyboard 200 Numerical Control Device

Claims (6)

In a display system in which at least one control device on a network and a display command related to display generated by the control device are received and processed to display a screen, the display system is connected.
The controller is
A means for permitting connection to the display device which has initially requested connection;
Network address storage means for storing the network address of the display unit that is initially requested for connection;
Means for transmitting a display command to the display device that has requested connection;
Network address storage means for notifying the other display of the stored network address and storing the network address of the other display when a connection request is received from another display;
The indicator is
Means for transmitting a connection request to a control device to be connected;
Means for connecting to the control device and receiving a display command when connection is permitted from the control device;
A means for connecting to a display device of the notified network address and receiving a display command when the network address is notified without being permitted from the control device;
Means for processing the received display command and displaying the screen;
A display system comprising: means for transmitting a received display command to a display device having a connection request when a connection request is received from another display device. If any display is turned off,
A display requesting the connection immediately before the display whose power has been cut off, and a means for transmitting the network address of the display to the display requesting the previous connection or the control device;
The display system according to claim 1, wherein a display requesting connection after the display that has been turned off includes means for requesting connection to the control device.   The display system according to claim 2, wherein the network address storage unit stores the order of the display devices requested to be connected and the network address. If any display is turned off,
The control device transmits the network address of the display unit that issued the connection request to the display unit that issued the connection request immediately after the display unit that was turned off. Means to
The display device notified of the network address, means for requesting connection to the display device of the notified network address;
The display system according to claim 1, further comprising: The display system according to claim 1 , wherein the display unit includes a unit that changes a network address of a control device to be connected. The indicator has key input means,
6. The information processing apparatus according to claim 1, further comprising: a display unit that has issued a connection request before connecting information input by the key input unit, or a transmission unit that transmits the information to the control device. Display system.

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