Method for generating network configuration information and communication device

Abstract

Method for generating network configuration information to produce information indicating a network configuration of a network system defined by a plurality of communication devices (11 to 18) and a plurality of networks (N / W (1) to N / W (4)), the method comprising: A first step in which at least one (13) of the communication devices generates and stores network configuration information, the network configuration information being defined as a pair consisting of a network name of a network (N / W (2)) to which the at least one communication device belongs and a network name of a network (N / W (1)) that is adjacent to the network to which the at least one communication device belongs;and a second step in which, when each of the communication devices receives the network configuration information stored in another of the communication devices, each communication device stores the received network configuration information.

Description

Field of InterestThe present invention relates to a method for generating information indicative of a connection relationship between a plurality of networks of a system.BackgroundSome methods for generating network configuration information in a system defined by a plurality of networks have been proposed so far.For a certain proposed method, in a control system including a plurality of programmable logic controllers (PLCs) connected to each other via networks, network configuration information and online connection paths are collected from the PLCs, and a connection relationship between the networks is calculated based on the collected information (e.g., in Patent Literature 1). For another proposed similar method, in a system in which a plurality of PLCs are connected via communication units to communication networks connected in a hierarchical structure, the type and the station number of each communication unit and the type of each programmable logic controller are determined via the communication networks, thereby calculating a connection relationship between the networks (e.g., in Patent Literature 2).Citation ListPatent LiteraturePatent Literature 1: International Publication No. WO 2008 / 146380Patent Literature 2: Japanese Patent Application Laid-Open No. H4-32905OverviewTechnical ProblemFor a conventional method of generating network configuration information, network information is generated according to an instruction of an external terminal in an PLC main device, which results in a problem of a high processing load on a CPU main unit of the PLC main device.The present invention has been made in view of the above, and an object of the present invention is to enable a communication device to predominantly generate information indicating a connection relationship between a plurality of networks of a system.Solution of the ProblemTo achieve the above object, the present invention provides a method for generating network configuration information to generate information indicating a network configuration of a network system defined by a plurality of communication devices and a plurality of networks, the method comprising:A step in which at least one of the communication devices generates and stores network configuration information, the network configuration information being defined as a pair of a network name of a network to which the at least one communication device belongs and a network name of a network disposed adjacent to the network to which the at least one communication device belongs; anda step in which, when each communication device receives, from another communication device, the network configuration information stored in the other communication device, each communication device stores the obtained network configuration information.Advantageous Effects of the InventionAccording to the present invention, it is possible for the communication devices to cooperate mainly with another to generate the information indicating a connection relationship between the networks.Brief Description of the DrawingsFIG. 1 is a diagram illustrating a configuration example of a communication system according to an embodiment. FIG. 2 is an operation flowchart according to the embodiment. FIG. 3 is a diagram illustrating an example of a network configuration information management table according to the embodiment. FIG. 4 is a block diagram illustrating a functional configuration of a gateway unit according to the embodiment. FIG. 5 is a diagram illustrating a hardware configuration of the gateway unit according to the embodiment. FIG. 6 is a block diagram illustrating a functional configuration of a display device according to the embodiment. FIG. 7 is a diagram illustrating a flowchart of an operation of a configuration information analysis unit. FIG. 8 is a diagram illustrating an example of a network configuration diagram according to the embodiment. FIG. 9-1 is a diagram illustrating a process for generating the network configuration diagram according to the embodiment. FIG. 9-2 is a diagram illustrating a process for generating the network configuration diagram according to the embodiment. FIG. 9-3 is a diagram illustrating a process for generating the network configuration diagram according to the embodiment.DESCRIPTION OF THE EMBODIMENTSAn embodiment of a method for generating network configuration information according to the present invention will be described below in detail with reference to the accompanying drawings. The present invention is not limited to the embodiment.EmbodimentFIG. 1 illustrates a configuration example of a network system according to an embodiment of the present invention. An PLC 41 includes a gateway unit 11. an PLC 42 includes gateway units 12 and 13. an PLC 43 includes gateway units 14, 15 and 16. an PLC 44 includes a gateway unit 17. an PLC 45 includes a gateway unit 18. in addition to the gateway unit, each PLC includes a combination of a plurality of units such as a power unit, a CPU unit that controls the entire PLC, a moving unit for performing positioning control on an object to be moved, and an input / output unit that receives or outputs a voltage / current signal. Further, a display device 50 is connected to an PLC 44. The display device 50 is a device for displaying and editing setting information of the PLC 44 and the other PLCs 41, 42, 43, and 45 connected to the display device 50 via network lines.The gateway units 11 to 18 of the PLCs 41 to 45 are connected to each other via the network lines 21 to 24. The gateway unit 12 and the gateway unit 13 are interconnected via a bus 31. The gateway unit 14, the gateway unit 15 and the gateway unit 16 are connected to each other via a bus 32. Although not shown, a plurality of units of each PLC are connected to each other via a bus.Each gateway unit belonging to a network is assigned an identification number (a network number) of the corresponding network. Each gateway is likewise assigned its own identification number (a station number). In FIG. 1, numerical values appearing in the block designating the gateway unit represent a network number and a station number respectively assigned to the gateway unit. The appearance of "2-1" in the block designating the gateway unit 13 indicates, for example, that the network number "2" and the station number "1" are assigned to the gateway unit 13. Gateway units which are connected to one another via one of the network lines 21 to 24 are assigned to the same network number. Gateway units connected to each other via one of the buses 31 and 32 are assigned different network numbers. In the present specification, a gateway unit is an example of a communication device. The communication device in the present specification is not limited to a gateway unit which is one of the units defining an PLC. For example, a portion of the communication device may be an independent gateway device connected to an PLC only via a network line. Further, although an PLC network is described in the present embodiment, the present invention may be applied to another network system that does not include an PLC. Although the present embodiment uses an identification number (a network number) as information for identifying a network, the information for identification may be represented by other characters or symbols instead of a number. The present description uses the term "network name" that includes the number and the other characters or symbols.Each of the network lines 21 to 24 is, for example, a Ethernet® line or an RS-232 / 422 line. Furthermore, not all network lines 21 to 24 are necessarily network lines of the same type. The network lines 21 to 24 may be different types of network lines. For example, both the network line 21 and the network line 22 may be a Ethernet® line, or a combination in which the network line 21 is a Ethernet® line and the network line 22 is an RS-232 line may be used.The bus including the buses 31 and 32 is configured to couple a plurality of units defining each PLC, a bus board or a system bus is configured to couple physical, adjacent devices, and to use a communication standard such as SATA or PCI EXPRESS. The aforementioned bus comprising buses 31 and 32 is also referred to as an "internal bus" in the present specification because the bus couples the units defining each PLC.FIG. 2 is a flowchart illustrating a process related to generation of network configuration information in the embodiment of the present invention. Referring to FIG. 2, an operation until pieces of network configuration information of the entire network system are collected in the gateway unit 17 will be described.First, when each gateway unit is activated, a process of generating network configuration information is started so that each gateway unit performs a configuration information generation process of collecting information of another gateway unit connected thereto via a bus within the corresponding PLC to a network to which the other gateway unit belongs, thereby generating information indicating a connection relationship between the networks (network configuration information) (S 11).The network configuration information is defined as a pair of: a network number 'NA1' of a network acting as a base network; and a network number 'NA2' of a network adjacent to the base network. In the present specification, a relationship in which networks are adjacent to each other means a relationship between different networks including different communication devices connected to each other via a bus (an internal bus). For the configuration in FIG. 1, the gateway units 14, 15 and 16 are connected to each other via the bus 32, and the communication devices 14, 15 and 16 belong to a second, third and fourth network, respectively. Therefore, the second, third and fourth networks are the networks that are adjacent to each other. The network configuration information is configured in a manner such that NA 1 indicates a network number of the nearer one of the adjacent networks to the gateway unit that functions as the reference gateway unit that manages the network information, and NA 2 indicates a network number farther from the reference gateway unit.In the configuration information generation process (S 11), each gateway unit generates the network configuration information NA 1 and NA 2: NA 1 indicates a network number of a network to which the gateway unit belongs; and NA 2 indicates a network number of a network adjacent to the network whose network number is denoted by NA 1, so that each gateway unit stores the pair of NA 1 and NA 2 in a table (a network configuration information management table) that manages the network configuration information of that gateway unit. If no information is adjacent to a network belonging to the network to which a gateway unit belongs, for example, if no gateway unit is connected to such a gateway unit via a bus, the network configuration information is empty.For example, the gateway unit 13 belongs to a network of the network number 2, and a network of the network number 1 is adjacent to this network of the network number 1. Therefore, the network configuration information (NA 1, NA 2) generated in the configuration information generation process and stored in a network configuration information management table of the gateway unit 13 is (2, 1). The gateway unit 14 belongs to the network of the network number 2 disposed adjacent to the networks of the network numbers 3 and 4. Therefore, network configuration information (NA1, NA2) generated and stored in a network configuration information management table of the gateway unit 14 is (2,3) and (2,4). Further, the gateway unit 15 belongs to the network of the network number 3 disposed adjacent to the networks of the network numbers 2 and 4. Therefore, the network configuration information (NA1, NA2) generated and stored in a network configuration information management table of the gateway unit 15 is (3,2) and (3,4). The gateway unit 17 belonging to the network number 3 cannot obtain information on a network adjacent thereto in S 11. As a result, no network configuration information is generated and a network configuration information management table is empty.Next, a gateway unit performs a configuration information transmission process (S 12) for transmitting generated network configuration information to another gateway unit. In the configuration information transmission process, each gateway unit transmits network configuration information generated in the configuration information generation process to another gateway unit via a network line.For example, the gateway unit 13 stores generated network configuration information in transmission data, and transmits the transmission data to the gateway unit 14 which is another device on a network line (the gateway unit 13 does not transmit the transmission data to the gateway unit 12 which is another device connected via a bus). Meanwhile, the gateway unit 15 stores generated network configuration information in transmission data, and transmits the transmission data to the gateway unit 17 which is another device on a network line. Further, although not illustrated, the gateway unit 14 transmits generated network configuration information to the gateway unit 13, the gateway units 16 and 12 transmit generated network configuration information to the gateway units 18 and 11, respectively.Upon receiving data transmitted from another gateway unit in the configuration information transmission process (S 12), each gateway unit performs a configuration information reception process (S 13) to extract the network configuration information stored in the received data and store the extracted network configuration information. In the configuration information receiving process, each gateway unit first extracts network configuration information stored in received data, and then adds the extracted network configuration information to a self-managed network configuration information management table.For example, the gateway unit 14 receives, from the gateway unit 13, network configuration information (NA 1, NA 2) which is (2, 1). As a result, the network configuration information (NA1, NA2) stored by the gateway unit 14 in the network configuration information management table is (2, 1), (2, 3) and (2, 4). The gateway unit 17 receives network configuration information (NA 1, NA 2) from the gateway unit 15, which is (3, 2) and (3, 4). As a result, the network configuration information (NA1, NA2) stored by the gateway unit 17 in the network configuration information management table is (3, 2) and (3, 4).Each gateway unit that has finished the configuration information receiving process stores network configuration information received in the configuration information receiving process in a transmission packet, and transmits the packet to another gateway unit via a bus (S 14). Note that only when new network configuration information is obtained in the immediately above configuration information reception process (S 13), each gateway unit transmits the network configuration information to another gateway unit. That is, when new network configuration information is not received, the gateway unit does not transmit the network configuration information to another gateway unit. Further, when network configuration information is to be transmitted to a gateway unit but is already stored by such a gateway unit, it is unnecessary to transmit this information. It is advantageous not to transmit this unnecessary information because the non-transmission of unnecessary information reduces the transmission traffic.For example, the gateway unit 14 ( 2, 1) which is network configuration information (NA 1, NA 2) received from the gateway unit 13 in S 13 which is an immediately preceding step, transmits to the gateway unit 15 and 16 via the bus 32, and further, the gateway unit 13 ( 2, 3) and ( 2, 4) which is network configuration information (NA 1, NA 2) received from the gateway unit 14 in S 13 which is an immediately preceding step, transmits to the gateway unit 12 via the bus 31.Subsequently, a gateway unit that has received network configuration information performs the reception process of the configuration information, stores the received network configuration information in a transmission packet, and transmits the transmission packet to another gateway unit in the same manner as explained above (S 15 and S 16). As already stated above, each gateway unit sends the information to another gateway unit only upon receipt of new network configuration information. It is not necessary to transmit information if such information is already stored by a gateway unit which would otherwise receive the information. It is advisable not to transmit such information.For example, the gateway unit 15(2, 1) which is network configuration information (NA1, NA2) received from the gateway unit 14 in a reception process of the configuration information transmits to the gateway unit 17 via the network line 23 (S15). Of the network configuration information (3, 2) and (3, 4) which is network configuration information (NA 1, NA 2) stored by the gateway unit 15, information is already stored by the gateway unit 17. Therefore, it is not necessary to transmit the information (3, 2) and (3, 4) to the gateway unit 17.Subsequently, in a bus, upon receiving the new network configuration information from a network line, a process for transmitting new network configuration information to another gateway unit is performed, while upon receiving the new network configuration, a process for transmitting new network configuration information to another gateway unit in a network line from a bus is performed. These processes are repeated until no more new information has to be transmitted.For example, there is no gateway unit connected to the gateway unit 17 via a bus. Therefore, after a reception process of the configuration information (S 17), no transmission process to another gateway unit is performed. Further, in the configuration of the present embodiment, transmission of network configuration information to the receiving unit 17 is not performed after the reception process of the configuration information (S 17), so that the network configuration information management table is completed in the reception process of the configuration information (S 17).FIG. 3 is a network configuration information management table stored by the gateway unit 17 after completion of the reception process of the configuration information (S 17) in the gateway unit 17.FIG. 4 is a block diagram illustrating a functional configuration of a gateway unit in the communication system in FIG. 1. In FIG. 4, the gateway unit 11 includes a receiving unit 111, a received data processing unit 112, a transmission unit 113, a transmission data creation unit 114, an information storage unit 115, and a configuration information creation unit 116.The configuration information creation unit 116 generates network configuration information and registers the generated network configuration information in a network configuration information management table stored by the information storage unit 115.The received data processing unit 112 extracts network configuration information from the received data, and registers the extracted network configuration information in the network configuration information management table stored by the information storage unit 115.In order to ensure that the gateway unit 11 can transmit data, the transmission data creation unit 114 first creates transmission data. The transmission data creation unit 114 reads out network configuration information stored in the information storage unit 115 and stores the information in the generated transmission data. Thereafter, the transmission unit 113 transmits the created transmission data.FIG. 5 is a diagram illustrating a hardware configuration of the gateway unit 11 illustrated in FIG. 4. The gateway unit 11 may be implemented by using a network interface 121, a bus interface 122, a memory 123, and a processor 124. The network interface 121 is a communication interface for connection to an external device via a network line. The bus interface is a communication interface for connection to another PLC unit via a bus. The memory 123 is a storage unit that stores therein a computer program such as software and firmware. The processor 124 is a processing circuit that reads out and executes a computer program stored in the memory 123. The memory 123 is a nonvolatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, and a magnetic disk, or the like. The processor 124 is a CPU (Central Processing Unit), a processing device, a computing device, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), or the like.The function of the receiving unit 111 of the gateway unit 11 and the function of the transmitting unit 113 are implemented via the network interface 121 or the bus interface 122. The functions of the received data processing unit 112 and the transmission data creation unit 114 of the gateway unit 11 are implemented by the processor 124 for executing a procedure described in a computer program. Further, the function of the information storage unit 115 of the gateway unit 11 is implemented by the memory 123.FIG. 6 is a block diagram illustrating a functional configuration of the display apparatus 50 for displaying a network configuration information diagram. In FIG. 6, the display device 50 includes a receiving unit 211, a received data processing unit 212, an information storage unit 213, a configuration information analysis unit 214, and a display unit 215.The received data processing unit 212 of the display device 50 analyzes data received by the receiving unit 211. The received data processing unit 212 extracts network configuration information from received data and registers the extracted network configuration information in a network configuration information management table stored by the information storage unit 213.The configuration information analysis unit 214 reads the network configuration information stored in the information storage unit 213, analyzes the content of the read information, and draws a network configuration diagram on the display unit 215.FIG. 7 is a diagram illustrating a flowchart of a process of a configuration information analysis process in the configuration information analysis unit 214. First, network configuration information is acquired from the information storage unit 213 (S 21).Next, the own network number is displayed in an upper left area of the display unit 215 (S 22), and the own network number is set as an "object network number" (S 23).Thereafter, a network number from a 'network adjacent to a network having the 'object network number' is drawn on the display unit 215 (the display position is a lower right area of a network of the 'object network number') (S 25). A connecting line is then drawn between the network number set as "object network number" and the network number drawn in S25 (S26).After the connecting line is drawn, the network number is set to the "object network" from the network drawn in S25 (S27). Subsequently, the operations S 25 to S 27 are repeated until all the networks are drawn (S 24).FIG. 8 is a diagram illustrating a generation example of a network configuration diagram in the communication system in FIG. 1. Drawing lines from 'NET3' to 'NET2' and 'NET4' in Fig. 8 indicates that a network of network number 3 is adjacent to a network of network number 2 and a network of network number 4. Drawing a line from 'NET2' to 'NET1' indicates that the network of network number 2 is adjacent to a network of network number 1.FIGS. 9-1, 9-2 and 9-3 are diagrams illustrating a flow of the operations for generating the network configuration diagram in FIG. 8 from the network configuration information management table in FIG. 3. First, 'NET3' representing a network number 3 which is a network number of its own network is drawn as shown in Fig. 9-1. Next, 'NET2' representing a network number 2 and 'NET4' representing a network number 4 are drawn connected by lines of 'NET3' as shown in Fig. 9-2, because it is understood from the network configuration information management table that networks of the network numbers 2 and 4 are adjacent to the network of the network number 3. Finally, 'NET1' representing a network number 1 is drawn connected by a line with 'NET2' as shown in Fig. 9-3 because it is understood from the network configuration information management table that a network of the network number 1 is adjacent to the network of the network number 2.In the configuration described in the present embodiment, activation of each gateway unit provides a trigger to start a process for generating network configuration information so that a network configuration information management table of each gateway unit is completed. With this configuration, it is possible to obtain information that quickly describes a network configuration of the entire network, compared to a case where a request from the outside serves as a trigger to start generating the network configuration information.On the other hand, the generation of network configuration information may be started by using a request from the outside as a trigger. This case is also significantly more advantageous compared to a known technique, since e.g. the communication scope is suppressed.The configuration of the present embodiment allows the gateway units to predominantly cooperate with another to generate information indicating a network configuration of the entire system. As a result, a load on a CPU unit can also be reduced.The configurations described in the above embodiment are merely examples of the content of the present invention. The configurations may be combined with other known techniques, and a part of each configuration may be omitted or changed without departing from the gist of the present invention.Industrial applicabilityAs described above, the method for generating network configuration information according to the present invention is suitable for a network system using a plurality of communication devices.List of reference characters11 Examples of the present disclosure include the following examples of the gateway unit (communication device) 21 to 24 network line 31, 32 bus 41 to 45 PLC (Programmable Logic Controller) 50 display device 111 reception unit 112 received data processing unit 113 transmission unit 114 transmission data creation unit 115 information storage unit 116 configuration information creation unit 121 network interface 122 bus interface 123 memory 124 processor 211 reception unit 212 received data processing unit 213 information storage unit 214 configuration information analysis unit 215 display unit.

Claims

A method of generating network configuration information to generate information indicative of a network configuration from a network system defined by a plurality of communication devices (11 to 18) and a plurality of networks (N / W (1) to N / W (4)), the method comprising: a first step in which at least one (13) of the communication devices generates and stores network configuration information, the network configuration information being defined as a pair of a network name of a network (N / W (2)) to which the at least one communication device belongs and a network name of a network (N / W (1)) disposed adjacent to the network to which the at least one communication device belongs; and a second step in, when each of the communication devices receives, from another one of the communication devices, the network configuration information stored in the another communication device, each communication device stores the obtained network configuration information.The method for generating network configuration information according to claim 1, wherein the first step and the second step allow each of the communication devices (11 to 18) to acquire the network configuration information indicated as the pair of the network names of the networks (N / W (2), N / W (1)) arranged adjacent to each other and information indicating the network configuration of the entire network system.The method for generating network configuration information according to claim 1 or 2, wherein the communication devices (11 to 18) include a communication device (13) belonging to one of the networks (N / W (2), N / W (1)) adjacent to each other and a communication device (17) belonging to one of the networks not adjacent to any network, and wherein the communication device belonging to one of the networks adjacent to each other generates and stores the network configuration information in the first step, and the communication device belonging to the one of the networks not adjacent to any network does not generate network configuration information.The method for generating network configuration information according to any one of claims 1 to 3, wherein each of the communication devices (11 to 18) that receives the network configuration information from the other communication device comprises a communication device connected via a network or a bus to another communication device different from the other communication device, and wherein the communication device connected via the network or the bus to the other communication device different from the other communication device transmits the network configuration information to the communication device connected thereto via the network or the bus.A method of generating network configuration information to generate information indicative of a network configuration from a network system defined by a plurality of communication devices (11 to 18) and a plurality of networks (N / W (1) to N / W (4)), the method comprising: a step of a first communication device (13) generating network configuration information, wherein the network configuration information is defined as a pair of a network name of a network (N / W (2)) to which the first communication device belongs and a network name of a network (N / W (1)) disposed adjacent to the network to which the first communication device belongs; and a step in which the first communication device transmits the network configuration information to a second communication device (14) via the network to which the first communication device belongs.The method for generating network configuration information according to claim 5, further comprising a step in which the second communication device (14) adds the received network configuration information to a network configuration information management table managed by the second communication device.The method for generating network configuration information according to claim 5 or 6, further comprising a step in which the second communication device (14) transmits the network configuration information to a third communication device (15) connected to the second communication device via an internal bus.The method for generating network configuration information according to any one of claims 5 to 7, further comprising a step of, when the first communication device (13) receives additional network management information from the second communication device (14) via the network to which the first communication device belongs, the first communication device transmitting the additional network management information to a third communication device (12) connected to the adjacent network.A communication device (13) comprising: a bus interface unit (122); and a network interface unit (121), wherein the communication device is connected to a first other communication device (12) via the bus interface unit and is connected to a network (N / W (2)) via the network interface unit, wherein the communication device transmits network work configuration information to a second other communication device (14) connected thereto via the network interface unit, and wherein the network configuration information is defined as a pair of a network name of a network (N / W (1)) to which the first other communication device is connected and a network name of the network connected to the communication device via the network interface unit.The communication device according to claim 9, wherein when the communication device receives additional network management information via the network interface unit (121) from the second other communication device (14) connected thereto, the communication device transmits the network configuration information to the first other communication device (12) connected thereto via the bus interface unit (122).The communication apparatus according to claim 9 or 10, further comprising a memory (123) for storing therein the network configuration information.The communication device according to any one of claims 9 to 11, wherein the communication device is a gateway unit of a programmable logic controller (42).A communication device (13) comprising: a bus interface unit (122); and a network interface unit (121), wherein the communication device is connected to a first other communication device (14) via the network interface unit, wherein when the communication device receives network configuration information from the first other communication device, the communication device transmits the network configuration information to a second other communication device (12) connected thereto via the bus interface unit, and wherein the network configuration information is defined as a pair of a network name of a network (N / W (2)) to which the first other communication device is connected and a network name of a network (N / W (1)) disposed adjacent to the network.The communication apparatus according to claim 13, further comprising a memory (123) for storing therein network configuration information.The communication device according to claim 13 or 14, wherein the communication device is a gateway unit of a programmable logic controller (42).

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