Connection control device, connection control system and program

Abstract

The device comprises a connection control device, a connection control system, and a program capable of ensuring the connection of a device of a predetermined type. According to one embodiment, a connection control device includes a determination unit and a connection control unit. The determination unit establishes whether a first device from among several types is a device of a first type. When the connection control unit receives a request from the first device to connect to a second device, the connection control unit permits the connection to the second device if the number of possible connections is greater than or equal to (N+1-(number of first devices of the first type that have established a connection to the second device)) out of the number of possible connections (where N is an integer greater than or equal to 1), and rejects the connection to the second device if this is not the case.

Description

Technical field

[0001] The present invention relates to a connection control device, a connection control system and a program. State of the art

[0002] Among devices such as control devices for industrial plants, there are devices connected to a variety of display devices, including a predominantly used main display device and secondary display devices. Such devices incorporate technical means to limit the number of connectable display devices in order to prevent excessive consumption of resources, such as processors like CPUs (central processing units). Multiple display devices are used. List of cited writings Patent document

[0003] Patent document 1: Unexamined Japanese patent application with publication number 2015-128476 Disclosure of the invention Problems to be solved by the invention

[0004] However, with such devices, simply limiting the number of connections can result in the main display device being unable to establish a connection if the number of connections is already at its limit due to the auxiliary display devices.

[0005] The problem that the embodiments of the present invention are intended to solve is to provide a connection control device, a connection control system and a program that are capable of ensuring the connection or coupling of predetermined types of devices. Means to solve the problems

[0006] The connection control device of the embodiment comprises a determination unit and a connection control unit. The determination unit determines that a first device is a device of a first type among several types. When a connection request is received from the first device to the second device, and the first device is not a device of the first type, the connection control unit permits the connection with the second device if (N (where N is an integer greater than or equal to 1) + 1 - (the number of first devices of the first type that have established connections with the second device)) or more available connections exist, or the connection control unit rejects the connection with the second device if this is not the case. Effects of the invention

[0007] The present invention can ensure the connection or linking of devices of predetermined types. Brief description of the drawings Fig. 1 is a block diagram illustrating an example of the essential design of a display system according to the first embodiment and the components included in the display system; Fig. 2 is a flowchart that shows an example of the processing by the processor of the control device in Fig. 1 illustrated according to the first embodiment; Fig. 3 is a flowchart that shows an example of the processing by the display device's processor in Fig. 1 or the auxiliary display device in Fig. 4 illustrated according to the first and second embodiments; Fig. 4 is a block diagram illustrating an example of the essential design of a display system according to the second embodiment and the components included in the display system; Fig. 5 is a flowchart that shows an example of the processing by the processor of the control device in Fig. 4 illustrated according to the second embodiment; and Fig. 6 is a flowchart that shows an example of the processing by the processor of the main display device in Fig. 4 illustrated according to the second embodiment. Preferred embodiment of the invention

[0008] The display system according to several embodiments is described below with reference to the drawings. In each drawing used to describe the embodiments, the scale of each part may be changed as needed. Each drawing used to describe the embodiments may show a simplified setup for illustrative purposes. In the drawings and this description, identical reference numerals denote identical elements. [First embodiment]

[0009] Fig. Figure 1 is a block diagram illustrating an example of the essential structure of a display system 1 according to the first embodiment and the components included in the display system 1. The display system 1 is a system capable of controlling the connection between a control device 100 and several display units 200. For example, the display system 1 includes the control device 100, the display units 200, and industrial equipment 300. The number of devices included in the display system 1 is not limited. The display system 1 typically includes several display units 200. The display system 1 is an example of a connection control system.

[0010] The control device 100, the display devices 200, and the industrial equipment 300 are connected to a network NW. The network NW typically includes a communication network, which may be a private network, such as an intranet. The network NW typically includes a communication network, such as a LAN (Local Area Network). The network NW may be a communication network that includes the Internet. The network NW may be a communication network that includes a WAN (Wide Area Network). The network NW may be a wireless connection, a wired connection, or a combination of both. The network NW may be a communication network that includes a dedicated line or a public cellular network. Each device connected to the network NW typically communicates using TCP (Transmission Control Protocol) / IP (Internet Protocol).

[0011] The control device 100 is a device that controls the industrial plant 300 or the like. The control device 100 can establish connections with the display devices 200 up to a limit of connections. The control device 100 transmits video to each of the connected display devices 200. Establishing a connection means creating a session, establishing a link, or the like. The control device 100 has, for example, a processor 110, a ROM (read-only memory) 120, a RAM (random access memory) 130, an auxiliary storage device 140, a communication interface 150, and a control interface 160. A bus 170 or the like connects these components. In the first embodiment, the control device 100 is an example of the connection control device. The control device 100 is an example of the second device.

[0012] The processor 110 is the central part of a computer, performing the calculations and controls required for the operation of the control device 100 and carrying out various calculations and processing operations. The processor 110 may, for example, have a CPU, an MPU (microprocessor unit), a SoC (system on a chip), a DSP (digital signal processor), a GPU (graphics processing unit), an ASIC (application-specific integrated circuit), a PLD (programmable logic device), or an FPGA (field-programmable gate array), or the like. Alternatively, the processor 110 may be a combination of several of these components. The processor 110 may also be a combination of these components with hardware accelerators or the like.The processor 110 controls various functions of the control device 100 based on programs such as firmware, system software, and application software stored in the ROM 120 or the additional storage device 140. The processor 110 performs the processing described later based on these programs. The programs may be partially or completely integrated into the processor 110's circuitry.

[0013] The ROM 120 and RAM 130 are the computer's main memory devices, arranged around the processor 110. The ROM 120 is non-volatile memory used exclusively for reading data. For example, the ROM 120 stores firmware from the programs mentioned above. The ROM 120 also stores data used by the processor 110 when performing various processing operations. The RAM 130 is memory used for both reading and writing data. The RAM 130 serves as a workspace to temporarily store data used by the processor 110 when performing various processing operations. The RAM 130 is typically volatile memory.

[0014] Based on the aforementioned programs, the processor 110 functions as the authentication control unit 111 and the connection control unit 112. The authentication control unit 111 manages the authentication process. Details of the authentication process are described later. The connection control unit 112 manages the connection between the control device 100 and the display devices 200.

[0015] The auxiliary storage device 140 is the computer's auxiliary storage device, arranged around the processor 110. The auxiliary storage device 140 may contain, for example, an EEPROM (electrically erasable, programmable read-only memory), an HDD (hard disk drive), or flash memory. The auxiliary storage device 140 stores, for example, system software and application software from the aforementioned programs. The auxiliary storage device 140 also stores data used by the processor 110 during various processing operations, data generated by processing within the processor 110, and various configuration values.

[0016] The auxiliary storage device 140 stores a display database (DB) 141 and a login database (DB) 142. The display database 141 stores and manages whether each display device 200 is a main display device 200A or an auxiliary display device 200B. For example, the main display device 200A is a primarily used display device 200. The main display device 200A is, for example, a primary display device 200. The auxiliary display device 200B is, for example, a display device 200 that is not the main display device 200A. The auxiliary display device 200B is, for example, a display device 200 that is used secondarily. The auxiliary display device 200B is, for example, a display device 200 that is used as a remotely located device together with the control device 100.Display DB 141 stores whether each display device 200 is a primary display device 200A or an auxiliary display device 200B by linking classification information to the display ID (identifier) ​​of each display device 200. The display ID is a unique identification piece of information for each display device 200. The classification information indicates whether the associated display device 200 is a primary display device 200A or an auxiliary display device 200B. The number of display devices 200 that can be registered as primary display devices 200A in display DB 141 is normally one. However, display DB 141 can allow an upper limit of two or more, or an unlimited number. Processor 110 performs a control function to ensure that the number of primary display devices 200A registered in display DB 141 does not exceed the upper limit.Whether each display unit 200 is a main display unit 200A or an auxiliary display unit 200B is pre-registered in the display DB 141, for example, by the administrator or operator of the display system 1.

[0017] The display ID is, for example, the IP address, MAC (Media Access Control) address, or another unique number for each of the other display devices 200. The display ID can also be a login ID. The login ID is a unique identifier for each account used to log in to the control device 100. The account and login ID can be unique for each display device 200 or for each user. For example, a user is a person who uses the display device 200. If the account and login ID are unique for each user, the display device 200 is designated as either the primary display device 200A or the auxiliary display device 200B, depending on the user logging in.

[0018] The login database 142 stores and manages information required for authentication processing to determine whether an account can log in to the control device 100. Login database 142 stores combinations of login IDs and passwords by linking login IDs with passwords for each account.

[0019] The communication interface 150 is an interface for the control device 100 for communication via the network NW or similar. The control device 100 communicates with the display device 200 via the communication interface 150 and the network NW. The communication interface 150 connects to the network NW, for example, using a LAN cable or a wireless LAN.

[0020] The communication interface 150 can connect directly to and communicate with the display device 200 without using the network. This communication can be either wired or wireless. The communication interface 150 can connect to and communicate with the display device 200 using video communication interfaces such as DisplayPort, HDMI (High-Definition Multimedia Interface) (registered trademark), DVI (Digital Visual Interface), or SDI (Serial Digital Interface). The communication interface 150 can connect to and communicate with the display device 200 using a general-purpose communication interface such as USB (Universal Serial Bus). The communication interface 150 can connect to and communicate with the display device 200 using other standards.

[0021] The control interface 160 is an interface for the control device 100 for communication with the industrial plant 300. The control device 100 controls the industrial plant 300 via the control interface 160. The control interface 160 can be used jointly with the communication interface 150.

[0022] The bus 170 has a control bus, an address bus and a data bus or the like and transmits signals that are exchanged between the various components of the control device 100.

[0023] The display device 200 receives the video signals output by the control device 100. The display device 100 displays the video represented by the video signals. The display device 200 has, for example, a display such as an LCD (liquid crystal display) or an OEL (organic electroluminescent display). The display device 200 can be a smartphone, a tablet computer, a PC, or a server. The display device 200 has, for example, a processor 210, a ROM 220, a RAM 230, an auxiliary storage device 240, a communication interface 250, a display unit 260, and an input device 270. The bus 280 or the like connects these components. The display device 200 is an example of the first device. The main control device 100A is an example of the first type of the first device.

[0024] The processor 210 is the central component of a computer, performing the calculations and controls required for the operation of the display device 200 and carrying out various computations and processing operations. The processor 210 may, for example, have a CPU, MPU, SoC, DSP, GPU, ASIC, PLD, or FPGA. Alternatively, the processor 210 may be a combination of several of these components. The processor 210 may also include a combination of these components with hardware accelerators or the like. The processor 210 controls various functions of the display device 200 based on programs such as firmware, system software, and application software stored in the ROM 220 or in the additional storage device 240. The processor 210 performs the processing described later based on these programs. The programs may be partially or completely integrated into the processor 210's circuitry.

[0025] The ROM 220 and the RAM 230 are the computer's main memory devices, arranged around the processor 210. The ROM 220 is non-volatile memory used exclusively for reading data. For example, the ROM 220 stores firmware for the programs mentioned above. The ROM 220 also stores data used by the processor 210 when performing various processing operations. The RAM 230 is memory used for both reading and writing data. The RAM 230 serves as a workspace to temporarily store data used by the processor 210 when performing various processing operations. The RAM 230 is typically volatile memory.

[0026] Based on the aforementioned programs, processor 210 functions as an authentication request unit 211. The authentication request unit 211 makes connection and authentication requests. Details regarding authentication are described later.

[0027] The auxiliary storage device 240 is the computer's auxiliary storage device, arranged around the processor 210. The auxiliary storage device 240 may contain, for example, an EEPROM, an HDD, or flash memory. The auxiliary storage device 240 stores, for example, system software and application software from the aforementioned programs. The auxiliary storage device 240 also stores data used by the processor 210 during various processing operations, data generated by processing within the processor 210, and various configuration values.

[0028] The ROM 220, the RAM 230, or the additional storage device 240 stores the display ID of the display device 200 that contains these components. This storage can be temporary or non-temporary.

[0029] The communication interface 250 is an interface for the display device 200 for communication via the network NW or the like.

[0030] The display module 260 shows screen content to convey various information to the operators of the display unit 200. The display module 260 has, for example, a display such as an LCD (liquid crystal display) or an OEL (organic electroluminescent display). The display unit 260 can be built into the display unit 200 or be external. The display unit 260 is an example of a display unit for displaying video.

[0031] The input device 270 receives operator input from operators of the display device 200. The input device 270 may have, for example, a keyboard, keypad, touch-sensitive panel, mouse, or controller. The input device 270 can also be a voice input device. A touch-sensitive panel can also function as both a display device 200 and an input device 270. In this case, the display area of ​​the touch-sensitive panel functions as the display device 200. The pointing device used for touch input, which is contained within the touch-sensitive panel, functions as the input device 270.

[0032] The bus 280 has a control bus, an address bus and a data bus or the like, and transmits signals that are exchanged between the various components of the display device 200.

[0033] The industrial plants 300 include, for example, machine tools, manipulators, robot arms or robots.

[0034] Next, the operation of the display system 1 according to the first embodiment will be described with reference to Fig. 2 and Fig. 3 described. The details of the processing described in the following operation are examples, and various processing methods that can achieve similar results may be used as needed. Fig. Figure 2 is a flowchart illustrating an example of processing by processor 110 of control device 100. Processor 110 executes the in Fig. 2. Processing shown is based on the programs stored in the ROM 120, the additional storage device 140, or the like. Fig. Figure 3 is a flowchart illustrating an example of processing by processor 210 of display device 200. Processor 210 performs the following steps: Fig. 3. Processing shown is based on the programs stored in the ROM 220, the additional storage device 240 or the like.

[0035] In the Fig. In step ST31, as shown in Figure 3, the processor 210 of the display device 200 determines whether to establish a connection to the control device 100. For example, if an input is received instructing the connection to be established, the processor 210 determines that the connection should be established. This input could be, for example, an operator input to the input device 270 by the operator of the display device 200. Alternatively, the processor 210 determines that the connection should be established if information instructing the connection to be established is received from another device. Alternatively, the processor 210 can determine that the connection to the control device 100 should be established in a state where communication with the control device 100 is possible. If the processor 210 determines not to establish the connection to the control device 100, the determination in step ST31 is "No," and the processing in step ST31 is repeated.If, on the other hand, the processor 210 decides to establish the connection to the control device 100, the decision in step ST31 is Yes, and the processing continues to step ST32.

[0036] Processor 210 can skip processing in step ST31 and proceed to step ST32. This means that if control device 100 is not connected while the process is in Fig. Once the processing shown in section 3 is carried out, the processor 210 can automatically establish the connection to the control device 100.

[0037] In step ST32, processor 210 generates the first connection request. This first connection request contains, for example, a display ID, a login ID, and a password. The first connection request is information that instructs the control device 100 to perform authentication using the login ID and password. It also instructs the receiver to establish a connection with the display device 200, which is the source of the first connection request. The display ID is the ID stored in ROM 220, RAM 230, or the auxiliary storage device 240. That is, the display ID contained in the first connection request is the ID of the display device 200, the source of the first connection request. The login ID and password are entered, for example, by the operator of display device 200 via input device 270.Alternatively, processor 210 can retrieve the login ID and / or password from auxiliary storage device 240. In this case, auxiliary storage device 240 stores at least either the login ID or the password in advance. If the login ID is used as the display ID, the display ID and the login ID can be the same. After generating the first connection request, processor 210 instructs communication interface 250 to transmit the first connection request to control device 100. Upon receiving the transmission instruction, communication interface 250 transmits the first connection request to control device 100. The transmitted first connection request is received by communication interface 150 of control device 100. The processing in step ST32 is performed, for example, by authentication request unit 211.

[0038] Meanwhile, processor 110 of control device 100 is waiting in step ST11, which is in Fig. Figure 2 shows that the first connection request is received from communication interface 150. When the first connection request is received, processor 110 determines "Yes" in step ST11, and processing proceeds to step ST12.

[0039] In step ST12, processor 110 performs authentication using the login ID and password contained in the initial connection request received in step ST11. That is, if the login ID and password combination is correct, processor 110 performs the authentication. Conversely, processor 110 rejects authentication if the login ID and password combination is incorrect.

[0040] Processor 110 accesses login database 142 to check if the login ID contained in the first connection request received in step ST11 is stored in login database 142. If the login ID is stored in login database 142, processor 110 accesses login database 142 to check if the password contained in the first connection request is associated with the login ID. If the password is associated with the login ID in login database 142, processor 110 determines that the combination of login ID and password is correct.

[0041] Conversely, processor 110 determines that the combination of login ID and password is incorrect if the login ID contained in the first connection request received in step ST11 is not stored in the login database 142. Similarly, if the password contained in the first connection request is not linked to the login ID contained in the first connection request in the login database 142, processor 110 determines that the combination of login ID and password is incorrect. The processing in step ST12, for example, is performed by the authentication control unit 111.

[0042] In step ST13, processor 110 determines whether authentication was performed in the authentication processing in step ST12. If authentication was rejected, processor 110 determines "No" in step ST13, and the processing proceeds to step ST14.

[0043] In step ST14, processor 110 instructs communication interface 150 to send an initial rejection notification to display device 200, the source of the initial connection request. The initial rejection notification indicates that authentication was rejected during authentication processing. Upon receiving the transmission instruction, communication interface 150 sends the initial rejection notification to display device 200. The transmitted initial rejection notification is received by communication interface 250 of display device 200. After processor 110 completes the processing in step ST14, processing returns to step ST11.

[0044] If, on the other hand, authentication was performed in the authentication processing, processor 110 determines yes in step ST13, and the processing proceeds to step ST15.

[0045] In step ST15, processor 110 determines whether connection capacity is available. If the number of display devices 200 that have established connections with the control device 100 is less than the connection limit, processor 110 determines that connection capacity is available. If no connection capacity is available, processor 110 determines "No" in step ST15, and processing proceeds to step ST16.

[0046] In step ST16, processor 110 instructs communication interface 150 to transmit a second rejection message to display device 200, the source of the first connection request. The second rejection message indicates that no connection capacity is available. Upon receiving the transmission instruction, communication interface 150 transmits the second rejection message to display device 200. The transmitted second rejection message is received by communication interface 250 of display device 200. After processor 110 completes the processing in step ST16, processing returns to step ST11.

[0047] On the other hand, processor 110 determines "Yes" in step ST15 if there is free capacity for connections, and processing proceeds to step ST17.

[0048] In step ST17, processor 110 determines whether the main display device 200A is currently connected. That is, processor 110 determines whether at least one of the display devices 200 that have established connections with the control device 100 is the main display device 200A. If the main display device 200A is currently connected, processor 110 determines "Yes" in step ST17, and the processing continues to step ST18.

[0049] In step ST18, which is in Fig. As shown in Figure 2, the processor 110 of the control device 100 determines whether the display device 200, which is the source of the first connection request, is the main display device 200A. The processor 110 receives the display ID contained in the first connection request received in step ST11. The processor 110 then accesses the display DB 141 to obtain the classification information associated with the display ID. If the classification information indicates that the display device 200 is the main display device 200A, the processor 110 determines that the display device 200, which is the source of the first connection request, is the main display device 200A. If, on the other hand, the classification information indicates that the display device 200 is the auxiliary display device 200B, the processor 110 determines that the display device 200, which is the source of the first connection request, is the auxiliary display device 200B.If the display device 200, which is the source of the first connection request, is not the main display device 200A, the processor 110 determines No in step ST18, and processing proceeds to step ST19.

[0050] As described above, processor 110 acts as an example of the determining unit by performing the processing in step ST18, which determines that the first device out of the several types is a device of the first type.

[0051] In step ST19, processor 110 determines whether the number of available connections is two or more. If the number of available connections is one or less, processor 110 determines "No" in step ST19, and processing proceeds to step ST20.

[0052] In step ST20, processor 110 instructs communication interface 150 to send a second rejection message to display device 200, the source of the first connection request. Alternatively, processor 110 instructs communication interface 150 to send a third rejection message to display device 200, the source of the first connection request. The third rejection message indicates that, although connection capacity is available, the connection is only permitted for the main display device 200A. Upon receiving the transmission instruction, communication interface 150 transmits the second or third rejection message to display device 200. The transmitted second or third rejection message is received by communication interface 250 of display device 200.After processor 110 has completed the processing in step ST20, the processing returns to step ST11.

[0053] Meanwhile, the processor 210 of the display device 200 determines in step ST33, which is in Fig. Figure 3 shows whether a rejection notification was received from communication interface 250. The rejection notification is a collective term for the first three rejection notifications. If no rejection notification was received, processor 210 determines "No" in step ST33, and processing proceeds to step ST34.

[0054] In step ST34, processor 210 determines whether an authorization notification has been received from communication interface 250. If no authorization notification has been received, processor 210 determines "No" in step ST34, and processing returns to step ST33. Thus, processor 210 remains in a wait state and repeats steps ST33 and ST34 until a rejection or authorization notification is received.

[0055] If a rejection notification is received while processor 210 is in the wait state of steps ST33 and ST34, processor 210 determines yes in step ST33, and processing continues with step ST35.

[0056] In step ST35, processor 210 generates an image corresponding to the rejection screen. Processor 210 then instructs display device 200 to display the generated image. Upon receiving the display instruction, display device 200 shows the rejection screen content.

[0057] The rejection screen content is a screen message that informs the operator of display device 200 that display device 200 cannot establish a connection to control device 100. The rejection screen content includes, for example, an image indicating that display device 200 cannot establish a connection to control device 100, and an image indicating the reason why the connection cannot be established. Text is one type of image. If the received rejection notification is the first rejection notification, the reason the connection cannot be established is that authentication was rejected. If the received rejection notification is the second rejection notification, the reason the connection cannot be established is that there is no available connection capacity.If the received rejection notification is the third rejection notification, the connection cannot be established because, although connection capacity is available, the connection cannot be established because the device is not the main display device 200A. After processor 210 has completed the processing in step ST35, processing returns to step ST31.

[0058] If the main display unit 200A is not currently connected, the processor 110 determines the control device 100 in step ST17, which is in Fig. If the display device 200, which is the source of the first connection request, is 200A, the processor determines 110 in step ST18 as Yes, and the processing proceeds to step ST21. If the number of available connections is two or more, the processor determines 110 in step ST19 as Yes, and the processing proceeds to step ST21.

[0059] In step ST21, processor 110 instructs communication interface 150 to send an authorization notification to display device 200, which is the source of the initial connection request. The authorization notification indicates that the connection to control device 100 is permitted. Upon receiving the transmission instruction, communication interface 150 transmits the authorization notification to display device 200. The transmitted authorization notification is received by communication interface 250 of display device 200.

[0060] As described above, the processor 110, through processing in steps ST17 to ST21, allows the connection between the auxiliary display device 200B and the control device 100 if the main display device 200A is currently connected to the control device 100 and the number of available connections is one or more. If the main display device 200A is not currently connected to the control device 100 and the number of available connections is two or more, the processor 110 allows the connection between the auxiliary display device 200B and the control device 100. That is, if there are (2 - (the number of the first devices of the first type that have established connections to the second device)) or more available connections, the processor 110 allows the connection between the auxiliary display device 200B and the control device 100.If a connection request is received from the first device to the second device, and the first device is not a device of the first type, and if (2 - (the number of first devices of the first type that have established connections to the second device) or more connections are available, then processor 110, by performing the processing in steps ST17 to ST21, acts as an example of the connection control unit, allowing the connection to the second device and rejecting the connection to the second device if this is not the case.

[0061] If an authorization notification is received while processor 210 is in the wait state of steps ST33 and ST34, as shown in Fig. As shown in step 3, the processor determines 210 in step ST34 Yes, and the processing moves to step ST36.

[0062] In step ST36, the processor 210 works together with the control device 100 to establish connections with the control device 100.

[0063] Meanwhile, step ST22, which is in Fig. As shown in Figure 2, the processor 110 of the control device 100 is connected to the display device 200 to establish connections with the display device 200. Thus, the processing in step ST22 in Fig. 2 and step ST36 in Fig. Three connections are established between the control device 100 and the display device 200. The processing in steps ST15 to ST22, which are described in Fig. The process shown in 2 is, for example, carried out by the connection control unit 112.

[0064] In step ST23, processor 110 begins transmitting a video to display device 200 using the established connection. Communication interface 150 transmits the video to display device 200. The transmitted video is received by communication interface 250 of display device 200. After processor 110 has completed the processing in step ST23, processing returns to step ST11.

[0065] As described above, the processor 110 acts as an example of the receiving unit by controlling the communication interface 150 for receiving videos. This unit works in conjunction with the communication interface 150 to receive video data transmitted from the second device connected to the display unit.

[0066] Meanwhile, processor 210 of display device 200 controls step ST37, which is in Fig. Figure 3 shows the display module 260, which displays the video received from the communication interface 250. Based on this control, the display module 260 begins displaying the video.

[0067] In step ST38, processor 210 waits for the established connection to control device 100 to be terminated. The reason for the termination could be, for example, a communication error, a runtime error, or a lack of operation. For instance, if no operation occurs for a predetermined period—that is, if the time during which no operation takes place at display device 200 lasts for a predetermined period—processor 110 of control device 100 can terminate the established communication with display device 200.

[0068] If the established connection to the control device 100 is broken, processor 210 determines "Yes" in step ST38, and processing returns to step ST31. Alternatively, processor 210 can attempt to re-establish the connection, for example by returning to step ST32.

[0069] If the display device 200 that requested the connection to the control device 100 is the auxiliary display device 200B, the display system 1 of the first embodiment rejects the connection unless there are (2 - (the number of main display devices 200A that have established connections to the control device 100)) or more available connections to the control device 100. Therefore, the display system 1 of the first embodiment ensures that at least one main display device 200A can establish a connection to the control device 100. In other words, the display system 1 of the first embodiment ensures that a predetermined device type, the main display device 200A, can establish a connection to the control device 100.

[0070] According to the display system 1 of the first embodiment, the control device 100 controls the connection. Therefore, the main display device 200A does not need to include any special functions compared to the auxiliary display device 200B.

[0071] The first embodiment described above can be modified as follows. In the first embodiment, the control device 100 reserves one of the available connections for the main display device 200A. However, the control device 100 can reserve two or more of the available connections for the main display device 200A. Generally speaking, the control device 100 reserves N of the available connections for the main display device 200A. In this case, the processor 110 of the control device 100 determines in step ST17 whether N main display devices 200A are currently connected. In step ST19, the processor 110 determines whether (N + 1 - (the number of main display devices 200A that have made connections to the control device 100)) or more connections are available. N is an integer greater than or equal to 1.

[0072] Therefore, if in the display system 1 of the embodiment the display device 200 that has requested the connection to the control device 100 is the auxiliary display device 200B, the connection is rejected unless (N + 1 - (the number of main display devices 200A that have established connections to the control device 100)) or more connections to the control device 100 are available. Therefore, the display system 1 of the embodiment ensures that N main display devices 200A can establish a connection to the control device 100. [Second embodiment]

[0073] In the display system 1b of the second embodiment, the main display unit 200A controls the connection instead of the control device 100. The same sections as in the first embodiment can be omitted from the description of the second embodiment.

[0074] Fig. Figure 4 is a block diagram illustrating an example of the essential structure of the display system 1b according to the second embodiment and the components contained in the display system 1b. Fig. The illustration of industrial plant 300 is omitted in section 4. Fig. Figure 4 shows only one control device 100, one main display device 200A, and one auxiliary display device 200B, but the number of each of these devices is unlimited. Display system 1b is an example of the linking control system.

[0075] In the second embodiment, the processor 110 of the control device 100 does not need to function as the connection control unit 112. In the second embodiment, the processor 210 of the main display device 200A functions as the authentication request unit 211 and as the connection control unit 212. The processor 210 of the auxiliary display device 200B functions as the authentication request unit 211, as in the first embodiment.

[0076] In the second embodiment, the additional storage device 240 of the main display unit 200A stores the display DB 141. The additional storage device 140 of the control unit 100 does not need to store the display DB 141.

[0077] In the second embodiment, the main display unit 200A is an example of the connection control device.

[0078] Next, the operation of the display system 1 according to the second embodiment will be described with reference to Fig. 3, Fig. 5 and Fig. 6 described. The details of the processing described in the following operation are examples, and various processing methods that lead to similar results can be used as needed. Fig. Figure 5 is a flowchart illustrating an example of processing by processor 110 of control device 100. Processor 110 executes the in Fig. 5 processing based on the programs stored in the ROM 120, in the additional storage device 140 or the like. Fig. Figure 6 is a flowchart illustrating an example of processing by the 210 processor of the 200A main display unit. The 210 processor performs the tasks described in Fig. The processing described in Figure 6 is carried out based on the programs stored in the ROM 220, in the auxiliary storage device 240, or the like. The display devices 200, both the main display device 200A and the auxiliary display device 200B, execute the processing described in Figure 6. Fig. 3. The processing is carried out as in the first embodiment. The main display unit 200A performs the processing shown in Fig. 3 and Fig. 6. Processing is shown in parallel or sequentially.

[0079] In the second embodiment, the processor 210 of the display device 200 transmits in step ST32, which in Fig. Figure 3 shows the first connection request to the main display unit 200A instead of the control device 100. In step St 32, the processor 210 of the main display unit 200A transmits the first connection request to the processor 210 itself using a loopback address. Alternatively, the processor 210 of the main display unit 200A can input the first connection request into the program that is shown in Figure 3. Fig. The processing shown in Figure 6 is performed instead of being transmitted. The main display unit 200A's processor 210 transmits or similarly inputs other information to the processor 210 itself.

[0080] In the second embodiment, the processor 210 of the main display unit 200A performs the processing in the following instead of the processor 110 of the control device 100. Fig. The six illustrated steps ST11 and ST15 to ST21 are used. However, the “communication interface 150” in the description of the processing in steps ST11 and ST15 to ST21 in the first embodiment should be read as the “communication interface 250” in the second embodiment.

[0081] If the processor 210 determines "yes" in step ST11 in the second embodiment, the processing proceeds to step ST51.

[0082] In step ST51, processor 210 generates an authentication request. The authentication request contains the login ID and password, which are included in the first connection request received in step ST11. The authentication request is information that instructs the controller 100 to perform authentication using the login ID and password. After generating the authentication request, processor 210 instructs communication interface 150 to transmit the authentication request to the controller 100. Upon receiving the transmission instruction, communication interface 150 transmits the authentication request to the controller 100. The transmitted authentication request is received by communication interface 250 of the controller 100.

[0083] Meanwhile, processor 110 determines the control device 100 in step ST41, which is in Fig. Figure 5 shows whether an authentication request was received from communication interface 150. If no authentication request was received, processor 110 determines "No" in step ST41, and processing proceeds to step ST42.

[0084] In step ST42, processor 110 determines whether a second connection request has been received from communication interface 150. If no second connection request has been received, processor 110 determines "No" in step ST42, and processing returns to step ST41. Thus, processor 110 remains in a wait state and repeats steps ST41 and ST42 until an authentication request or a second connection request is received.

[0085] If an authentication request is received while processor 110 is in the wait state of steps ST41 and ST42, processor 110 determines yes in step ST41, and processing continues with step ST12.

[0086] In the second embodiment, the processor 110 performs the authentication processing in step ST12 using the login ID and password contained in the authentication request received in step ST41.

[0087] In the second embodiment, processing continues with step ST43 if processor 110 determines yes in step ST13.

[0088] In step ST43, processor 110 instructs communication interface 250 to send an authentication notification to the main display device 200A, which is the source of the authentication request. Upon receiving the transmission instruction, communication interface 250 transmits the authentication notification to the main display device 200A. The transmitted authentication notification is received by communication interface 150 of display device 200A. After processor 110 has completed the processing in step ST43, the processing returns to step ST41.

[0089] Meanwhile, the processor 210 of the main display unit 200A determines in step ST52, which is in Fig. Figure 6 shows whether an initial rejection notification was received from communication interface 250. If no initial rejection notification was received, processor 210 determines "No" in step ST52, and processing proceeds to step ST53.

[0090] In step ST53, processor 210 determines whether an authentication notification has been received from communication interface 250. If no authentication notification has been received, processor 210 determines "No" in step ST53, and processing returns to step ST52. Thus, processor 210 remains in a wait state and repeats steps ST52 and ST53 until a first rejection notification or an authentication notification is received.

[0091] If an initial rejection notification is received while processor 210 is in the wait state of steps ST52 and ST53, processor 210 determines Yes in step ST52, and processing continues with step ST14.

[0092] In step ST14, processor 210 can forward the first rejection notification received in step ST52 to display device 200. In step ST14, which is in Fig. As shown in Figure 5, processor 110 can send the first rejection notification not only to the main display device 200A, but also to the display device 200 that is the source of the first connection request. In this case, the main display device 200A performs the processing in step ST14, as shown in Figure 5. Fig. 6 shown, not shown.

[0093] If an authentication notification is received while processor 210 is in the wait state of steps ST52 and ST53, processor 210 determines Yes in step ST53, and processing proceeds to step ST15.

[0094] In the second embodiment, if the display ID contained in the first connection request received in step ST11 is the display ID that identifies the processor 210 itself, the processor 210 can determine in step ST18 that the display device 200, which is the source of the first connection request, is the main display device 200A. The display ID that presents the component itself is, for example, a loopback address. If the display ID contained in the first connection request is not the display ID that identifies the processor 210 itself, the processor 210 can determine that the display device 200, which is the source of the first connection request, is the auxiliary display device 200B.

[0095] After processor 210 has completed the processing in step ST21, processing continues with step ST54. In step ST54, processor 210 instructs communication interface 150 to send a second connection request to control device 100. The second connection request contains information that identifies the display device 200, which is the source of the first connection request. This second connection request is information that requests the establishment of a connection to display device 200. This information includes, for example, the display ID or IP address of the source. Upon receiving the transmission instruction, communication interface 150 transmits the second connection request to control device 100. The transmitted second connection request is received by communication interface 250 of control device 100.After processor 210 has completed the processing in step ST54, the processing returns to step ST11.

[0096] The processing in steps ST15 to ST21 and ST54, which are in Fig. The process shown in Figure 6 is, for example, executed by the connection control unit 212. By performing the processing in steps ST17 to ST21, in a case where a connection request is received from the first device to the second device and the first device is not a device of the first type, and if there are (2 - (the number of first devices of the first type that have established connections to the second device) or more available connections, then the processor 210 acts as an example of the connection control unit, allowing the connection to the second device and rejecting the connection to the second device if this is not the case. By performing the processing in step ST18, the processor 210 acts as an example of the determination unit, determining that the first device is a device of the first type among the multitude of types.

[0097] If a second connection request is received while processor 110 is in the wait state of steps ST41 and ST42, processor 110 determines yes in step ST42, and processing proceeds to step ST44.

[0098] In step ST44, processor 110 processes the connection setup with display device 200, which is specified by the second connection request received in step ST42. Processor 110 works with display device 200 to establish the connection in the same way as in step ST22. Fig. 2. That is, the control device 100 and the main display unit 200A establish the connection between the control device 100 and the display unit 200 through the processing in step ST44, as shown in Fig. 5, and step ST36, shown in Fig.3. Alternatively, the processor 110 can cooperate with the display device 200 and the main display device 200A, which is the source of the second connection request, to establish the connection. The control device 100 can establish the connection to the display device 200 directly without the main display device 200A, or it can establish the connection to the display device 200 via the main display device 200A. In this case, for example, connections are established between the control device 100 and the main display device 200A, and between the main display device 200A and the display device 200.

[0099] In step ST45, processor 110 begins transmitting video data to display device 200, which is designated by the second connection request, using the established connection. Communication interface 150 transmits the video data to display device 200. The transmitted video data is received by communication interface 250 of display device 200. Processor 110 can also transmit the video data to display device 200 via the main display device 200A, which is the source of the second connection request. That is, communication interface 150 transmits the video data to main display device 200A. The transmitted video data is received by communication interface 250 of main display device 200A. Main display device 200A, having received the video data, then transmits the video data to display device 200.After processor 110 has completed the processing in step ST45, the processing returns to step ST41.

[0100] In the display system 1b of the second embodiment, as in the first embodiment, at least one main display unit 200A can reliably connect to the control device 100. That is, the display system 1b of the second embodiment ensures that a predetermined device type, the main display unit 200A, can be connected to the control device 100.

[0101] According to the display system 1b of the second embodiment, the main display device 200A functions as a connection control unit 212. Thus, even in a case where the control device 100 does not function as a connection control unit 112, the display system 1b of the second embodiment can control the creation of connections to ensure that at least one main display device 200A can establish a reliable connection to the control device 100.

[0102] The second embodiment described above can be modified as follows. In the second embodiment, the main display unit 200A reserves one of the available connections for itself. However, the control unit 100 can reserve two or more of the available connections for the main display unit 200A. In general terms, the main display unit 200A reserves N of the available connections for itself. In this case, the processor 210 of the main display unit 200A determines in step ST17 whether N main display units 200A are currently connected. In step ST19, the processor 210 determines whether (N + 1 - (the number of main display units 200A that have made connections to the control unit 100)) or more connections are available.

[0103] If the display device 200 requesting connection to the control device 100 is the auxiliary display device 200B, the display system 1 of the embodiment rejects the connection unless (N + 1 - (the number of main display devices 200A that have established connections to the control device 100)) or more connections to the control device 100 are available. Consequently, the display system 1 of the embodiment ensures that N main display devices 200A can be reliably connected to the control device 100.

[0104] The processor 210 of the auxiliary display device 200B does not need to function as the authentication request unit 211. In this case, the main display device 200A serves as the authentication request unit 211 instead of the auxiliary display device 200B.

[0105] The above embodiments, namely the first and the second embodiment, can be modified as follows. In the above embodiments, the display device 200, which has been authenticated in the authentication process, can be connected to the control device 100. However, the authentication process may be unnecessary.

[0106] The processor 210 of the main display unit 200A can serve as an authentication control unit. That is, instead of the control device 100, the main display unit 200A can perform the authentication processing.

[0107] In the above embodiments, the display devices 200 can be classified into two types: the main display device 200A and the auxiliary display device 200B. However, the display devices 200 can also be classified into several types in another way. One of these types will be the first device type. The number of types can be three or more.

[0108] In the above embodiments, the devices connected to the control device 100 are display devices 200. However, the devices connected to the control device 100 can be other types of devices instead of the display devices 200.

[0109] In the embodiments described above, the control device 100, which controls the industrial plant 300, was described as an example of the interconnection control device of the embodiments. However, the interconnection control device of the embodiments is not limited to this. The interconnection control device of the embodiments can be a device that controls machines or equipment that are not industrial plants, such as a PC (personal computer), a server, or another computer.

[0110] In the above embodiments, part of the processing performed by the control device 100 can be performed by the display device 200. In the above embodiments, part of the processing performed by the display device 200 can be performed by the control device 100. In the above embodiments, part of the processing performed by the main display device 200A can be performed by the auxiliary display device 200B. In the above embodiments, part of the processing performed by the auxiliary display device 200B can be performed by the main display device 200A.

[0111] The processor 110 and the processor 210 can implement part or all of the processing implemented by the programs in the above embodiments using the essential structure of the circuits.

[0112] The programs implementing the processing of the embodiments are transferred, for example, in a state stored on a non-volatile recording medium within the device. However, the device can be shipped without the programs stored on it. The programs can be transferred separately and written to the device. The transfer of the programs can be accomplished, for example, by recording them on a removable non-volatile storage medium or by downloading them over a network such as the internet or a LAN.

[0113] The embodiments of the present invention have been described above as examples and do not limit the scope of the present invention. These embodiments can be implemented in various forms without altering the essence of the present invention. Explanation of reference symbols 1, 1b Display system 100 Control device 110, 210 processor 111 Authentication control unit 112 Connection control unit 120, 220 ROM 130, 230 RAM 140, 240 Additional storage device 141 Display DB or display database 142 Registration database 150, 250 communication interface 160 control interface 170, 280 Bus 200 Display unit 200a Main Display Unit 200b Auxiliary Display Unit 211 Authentication Request Unit 260 Display module or display unit 270 Input device 300 industrial plant QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2015-128476

[0003]

Claims

[1] A connection control device comprising: a determination unit that determines that a first device among multiple types is a device of a first type; and a connection control unit, wherein, when a request to connect to a second device is received from the first device and the first device is not a device of the first type, the connection control unit allows a connection to the second device if (N (where N is an integer greater than or equal to 1) + 1 - (a number of the first devices of the first type that have established a connection to the second device)) or more available connections are present, or the connection control unit otherwise rejects the connection to the second device. [2] The connection control device according to claim 1, wherein the connection control device is the second device. [3] The connection control device according to claim 1, wherein the connection control device is the first device of the first type. [4] The connection control device according to claim 1, wherein N is 1. [5] A connection control system comprising: a connection control device and a display device, wherein the connection control device comprises: a determination unit that determines that the display device among multiple types is the display device of a first type; and a connection control unit, wherein, when a request to connect to a second device is received from the display device and the display device is not the display device of the first type, the connection control unit allows a connection to the second device if (N (where N is an integer greater than or equal to 1) + 1 - (a number of display devices of the first type that have established a connection to the second device)) or more available connections are present, or the connection control unit otherwise rejects the connection to the second device, wherein the display device has: a receiving unit that receives video data transmitted from the second device connected to the display device; and a display unit that displays the video data. [6] A program that causes a processor included in a connection control device to operate as a determination unit that determines that a first device among multiple types is a device of a first type; and a connection control unit, wherein, when a request to connect to a second device is received from the first device and the first device is not a device of the first type, the connection control unit allows a connection to the second device if (N (where N is an integer greater than or equal to 1) + 1 - (a number of the first devices of the first type that have established a connection to the second device)) or more available connections are present, or the connection control unit otherwise rejects the connection to the second device.

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