WO2021033356A1

WO2021033356A1 - Control system and control method

Info

Publication number: WO2021033356A1
Application number: PCT/JP2020/009960
Authority: WO
Inventors: 久則五十嵐; 西山　佳秀
Original assignee: オムロン株式会社
Priority date: 2019-08-19
Filing date: 2020-03-09
Publication date: 2021-02-25
Also published as: JP2021034773A

Abstract

First and second units are respectively connected to first and second networks. The first and second units respectively have first and second ports connected to an internal network. The second unit has a router for relaying a packet using a first routing table, and a first setting unit for acquiring, from the first unit, a first network identifier for identifying the first network and first address information assigned to the first port, and associating and setting, in the first routing table, the first network identifier and the first address information. Consequently, the time and labor of network setting for performing communication between two devices respectively connected to the first and second units are reduced.

Description

Control system and control method

The present disclosure relates to a technique for relaying communication with an external device in a control system composed of a plurality of units.

At production sites using FA (Factory Automation), control units such as PLCs (Programmable Logic Controllers) connected to various equipment and various devices placed in each equipment are used. In recent years, control units that can be connected to external devices have become widespread. Regarding such a control unit, Patent Document 1 (Japanese Unexamined Patent Publication No. 2016-194808) discloses a PLC capable of accessing a database of an external device.

Japanese Unexamined Patent Publication No. 2016-194808

Various functional units can be connected to the control unit. As a functional unit, there is a relay unit that relays communication with an external device. The control unit and the functional unit are communicated via the internal network. In order to access the device connected to the control unit from the external device, the relay point from the network between the external device and the relay unit to the internal network and the network from the internal network to the network between the control unit and the device It is necessary to pass through the relay point. That is, the number of hops when accessing the device from an external device is at least 2. Therefore, it takes time and effort to set up the network for communication between the external device and the device.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to set up a network for communicating between two devices connected to the first unit and the second unit constituting a plurality of units, respectively. It is to provide a control system and a control method which can reduce the trouble of the above.

According to an example of the present disclosure, the control system is composed of a plurality of units. The plurality of units include a first unit connected to the first network and a second unit capable of communicating with the first unit via the internal network and connected to the second network. The first unit has a first port connected to the internal network. The second unit has a second port connected to the internal network. The second unit further includes a router and a first setting unit. The router relays the packet by using the first routing table in which the network identifier that identifies the network and the address information of the forwarding destination of the packet destined for the device connected to the network are associated with each other. The first setting unit acquires the first network identifier that identifies the first network from the first unit and the first address information assigned to the first port, and associates the first network identifier with the first address information. And set it in the first routing table.

According to this disclosure, a record in which the first network identifier and the first address information are associated with each other is automatically added to the first routing table. Therefore, it takes time and effort to manually set the network to access the device on the first network (hereinafter referred to as "first device") from the device on the second network (hereinafter referred to as "second device"). Is reduced. By using the first routing table automatically set in this way, when the router receives a packet destined for the first device from the second device, the router forwards the packet to the first port. Since the destination of the packet is the first device, the first unit outputs the packet to the first network. As a result, the first device can receive the packet from the second device.

In the above disclosure, the first unit further assigns the first address information to the first port and the second to the second port using a network identifier that is not used in the network settings of the plurality of units. It has an address allocation unit for assigning address information.

According to this disclosure, the first and second address information of each of the first and second ports on the internal network is automatically assigned. Therefore, the trouble of manually setting the network for accessing the first device from the second device is further reduced.

In the above disclosure, the first unit further has a communication unit and a second setting unit. The communication unit relays the packet using the second routing table in which the network identifier that identifies the network and the address information of the forwarding destination of the packet destined for the device connected to the network are associated with each other. The second setting unit sets the second network identifier that identifies the second network and the second address information assigned by the address assignment unit in the second routing table in association with each other.

According to this disclosure, a record in which the second network identifier and the second address information are associated is automatically set in the second routing table. Therefore, the trouble of manually setting the network for accessing the second device from the first device is reduced. By using the second routing table automatically set in this way, when the communication unit receives a packet destined for the second device from the first device, the communication unit forwards the packet to the second port. Since the destination of the packet is the second device, the router of the second unit outputs the packet to the second network. As a result, the second device can receive the packet from the first device.

In the above disclosure, the first unit further has a NAPT (Network Address Port Translation) processing unit for translating the source address and port number of the packet addressed to the first network. According to this disclosure, a plurality of second devices can be connected to the first device at the same time by using one address information.

In the above disclosure, the second unit and the device (second device) on the second network are connected by VPN (Virtual Private Network). According to this disclosure, the second device can operate as a device on the internal network.

According to an example of the present disclosure, a control method of a control system composed of a plurality of units includes the following first step and second step. The plurality of units include a first unit connected to the first network, and a second unit capable of communicating with the first unit using the internal network and connected to the second network. The first unit has a first port connected to the internal network. The second unit has a second port connected to the internal network. In the first step, the second unit acquires the first network identifier that identifies the first network from the first unit and the first address information assigned to the first port, and the first network identifier and the first address. This is a step to set a routing table associated with information. The second step is a step in which the second unit relays the packet using the routing table.

This disclosure also reduces the time and effort required to set up a network for communicating between two devices connected to the first unit and the second unit, which form a plurality of units.

According to the present disclosure, it is possible to reduce the time and effort required to set up a network for communicating between two devices connected to the first unit and the second unit, which constitute a plurality of units.

It is a figure which shows the configuration example of the control system which concerns on embodiment. It is a schematic diagram which shows the hardware configuration example of the control unit which comprises the control system according to this embodiment. It is a schematic diagram which shows the hardware configuration example of the relay unit which comprises the control system according to this embodiment. It is a figure which shows the functional configuration example of the control unit and a relay unit which make up a control system. It is a figure which shows the screen example for the network setting of a control unit. It is a figure which shows the screen example for network setting of a relay unit. It is a figure explaining the process of assigning an IP address to a port on an internal network. It is a figure explaining the routing table automatic setting for transfer to an internal network in a control unit. It is a figure explaining the routing table automatic setting for transfer to an internal network in a relay unit. It is a figure explaining the NAPT process. It is a sequence diagram which shows an example of network automatic setting.

An embodiment of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated.

§1 Application example First, an example of a situation in which the present invention is applied will be described with reference to FIG. FIG. 1 is a diagram showing a configuration example of a control system according to an embodiment.

The control system 1 includes a control unit 100 and a relay unit 200. The control system 1 may further include one or more functional units 300.

The control unit 100 is, for example, a PLC. The control unit 100 controls the control target according to a user program designed in advance. The control unit 100 includes a PLC engine 10 that executes a control calculation according to a user program or the like. The PLC engine 10 of the example shown in FIG. 1 has three ports 11 to 13.

Port 11 is connected to the internal network NW1. A relay unit 200 and a functional unit 300 are connected to the internal network NW1. As a result, the PLC engine 10 can communicate with the relay unit 200 and the functional unit 300 via the internal network NW1. For example, TCP / IP is adopted for the internal network NW1.

Port 12 is connected to network NW2. For example, a support device 500 is connected to the network NW2. As a result, the PLC engine 10 can communicate with the support device 500 via the network NW2.

As an example, the support device 500 is realized by using hardware (for example, a general-purpose personal computer) that follows a general-purpose architecture. The support device 500 provides a development environment such as creating a user program executed by the PLC engine 10 of the control unit 100 and setting various information of the control unit 100 and the relay unit 200.

Port 13 is connected to network NW3. One or more devices 400 are connected to the network NW3. As a result, the PLC engine 10 can communicate with the device 400 via the network NW3.

The device 400 includes, for example, various industrial devices for automating the production process. As an example, the device 400 includes another PLC, an HMI (Human Machine Interface), and a control target. Controlled objects include, for example, robot controllers that control arm robots, servo drivers that control servo motors, visual sensors for photographing workpieces, pressure sensors, temperature sensors, and other equipment used in the production process. ..

For networks NW2 and NW3, for example, industrial network protocols such as EtherCAT (registered trademark), EtherNet / IP (registered trademark), DeviceNet (registered trademark), and CompoNet (registered trademark) are adopted.

The relay unit 200 is connected to the control unit 100 and is in charge of the communication function with the external device. The relay unit 200 includes a router 20 that relays communication with an external device. The example router 20 shown in FIG. 1 has three ports 22 to 24.

Port 22 is connected to the internal network NW1. The port 23 is connected to the external network NW4. The router 20 relays communication between the external device 600 connected to the external network NW4 and the control unit 100 and the functional unit 300 connected to the internal network NW1.

Port 24 is connected to the external network NW5. The router 20 relays communication between the external device 700 connected to the external network NW5 and the control unit 100 and the functional unit 300 connected to the internal network NW1.

For example, Ethernet (registered trademark) is adopted for the external networks NW4 and NW5. In the example shown in FIG. 1, the external network NW4 is a WAN (Wide Area Network), and the external network NW5 is a LAN (Local Area Network).

The router 20 executes packet relay processing based on the preset routing table 25. The routing table 25 is a table in which a network identifier that identifies a network is associated with address information (IP address) of a transfer destination of a packet destined for a device connected to the network. When the router 20 receives a packet, it reads the IP address corresponding to the network identifier of the destination of the packet from the routing table. The router 20 forwards the packet to the read IP address.

The relay unit 200 further includes an application server 21. The application server 21 provides various services related to the control system 1. The application server 21 illustrated in FIG. 1 provides an authentication service that centrally manages user accounts for various units constituting the control system 1. Specifically, the application server 21 collates the user account acquired from the access source device with the registration information, and determines whether or not to allow access according to the collation result. When the application server 21 provides such an authentication service, the relay unit 200 operates as an authentication unit.

The application server 21 has a port 26 connected to the internal network NW1. The application server 21 acquires a user account and outputs an authentication result via the port 26.

The functional unit 300 provides various functions for realizing control of various control targets by the control system 1. The functional unit 300 may typically include an I / O unit, a safety I / O unit, a communication unit, a motion controller unit, a temperature control unit, a pulse counter unit, and the like.

In the control system 1 shown in FIG. 1, it is desired that the device 400 connected to the network NW3 can be accessed from the external device 600 connected to the external network NW4. If the device 400 can be accessed from the external device 600, the user can check the status of the device 400 via the external network NW4 which is a WAN even if he / she is in a remote place.

When the relay unit 200 is connected to the control unit 100, the user tends to interpret the control unit 100 and the relay unit 200 as being integrated. Therefore, the user expects to be able to access the device 400 using the external device 600 in the same way as when accessing the device 400 using the support device 500.

However, since the control unit 100 and the relay unit 200 are operating on different processors, an internal network NW1 is always constructed between the control unit 100 and the relay unit 200. Communication from the support device 500 to the device 400 may pass through a relay point between the network NW2 and the network NW3. On the other hand, communication from the external device 600 to the device 400 needs to pass through a relay point between the external network NW4 and the internal network NW1 and a relay point between the internal network NW1 and the network NW3. Therefore, the network setting for accessing the device 400 from the external device 600 is more complicated than the network setting for accessing the device 400 from the support device 500. Therefore, it takes time and effort to manually set the network for accessing the device 400 from the external device 600.

It is conceivable to attach a physical NIC (Network Interface Card) to the control unit 100 instead of the relay unit 200, and access the device 400 from the external device 600 via the physical NIC and the control unit 100. In this case, the trouble of network setting is simplified. However, since the physical NIC is not equipped with a processor, the function of the application server 21 shown in FIG. 1 is executed by the PLC engine 10 of the control unit 100. As a result, the computing load of the PLC engine 10 increases.

In the control system 1 according to the present embodiment, the following processing is performed in order to reduce the trouble of manually setting the network when accessing the device 400 from the external device 600 via the relay unit 200 including the application server 21. Will be executed.

First, the control unit 100 automatically assigns a valid IP address in the internal network NW1 to

ports

11, 22, 26 connected to the internal network NW1.

Next, the relay unit 200 receives from the control unit 100 the network identifier of the network NW3 connected to the port 13 of the PLC engine 10 and the IP address assigned to the port 11 in the internal network NW1. The relay unit 200 sets the routing unit 200 in the routing table 25 in association with the network identification received from the control unit 100 and the IP address of the port 11.

As a result, when the router 20 receives a packet destined for the device 400 connected to the network NW3 from the external device 600, the router 20 refers to the routing table 25 and forwards the packet to the port 11. Since the destination of the packet transferred to the port 11 is the device 400 connected to the network NW3, the PLC engine 10 outputs the packet from the port 13 to the network NW3. As a result, the device 400 can receive the packet from the external device 600.

As described above, according to the present embodiment, the network identifier of the network NW3 connected to the port 13 of the PLC engine 10 is associated with the address information (IP address) assigned to the port 11 in the internal network NW1. Is automatically set in the routing table 25. Therefore, the trouble of manually setting the network for accessing the device 400 from the external device 600 is reduced.

§2 Specific example Next, a specific example of the control system 1 according to the present embodiment will be described.

<A. Control unit hardware configuration example>
FIG. 2 is a schematic diagram showing a hardware configuration example of a control unit constituting a control system according to the present embodiment. As shown in FIG. 2, the control unit 100 has a processor 102 such as a CPU (Central Processing Unit) and a GPU (Graphical Processing Unit), a chipset 104, a main storage device 106, and secondary storage as main components. It includes a device 108, a USB (Universal Serial Bus) controller 112, a memory card interface 114,

network controllers

116, 118, an internal bus controller 122, and an indicator 124.

The processor 102 reads various programs stored in the secondary storage device 108, expands them in the main storage device 106, and executes them to realize control operations related to standard control and various processes as described later. .. The chipset 104 realizes the processing of the control unit 100 as a whole by mediating the exchange of data between the processor 102 and each component.

In addition to the system program, the secondary storage device 108 stores a user program that operates in the execution environment provided by the system program.

The USB controller 112 is in charge of exchanging data with an arbitrary information processing device via a USB connection.

The memory card interface 114 is configured so that the memory card 115 can be attached and detached, and data such as a control program and various settings can be written to the memory card 115, or data such as a control program and various settings can be written from the memory card 115. It is possible to read it.

Each of the

network controllers

116 and 118 is in charge of exchanging data with arbitrary devices (for example, support device 500 and device 400) via the network.

Network controllers

116, 118 may employ industrial network protocols such as EtherCAT®, EtherNet / IP®, DeviceNet®, CompoNet®.

The internal bus controller 122 is in charge of exchanging data with the

relay units

200, 1 or a plurality of functional units 300 constituting the control system 1. TCP / IP is used for the internal bus.

The indicator 124 notifies the operating state of the control unit 100 and the like, and is composed of one or a plurality of LEDs arranged on the surface of the unit.

FIG. 2 shows a configuration example in which the necessary functions are provided by the processor 102 executing the program, and some or all of these provided functions are provided by a dedicated hardware circuit (for example, ASIC). It may be implemented using (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array). Alternatively, the main part of the control unit 100 may be realized by using hardware that follows a general-purpose architecture (for example, an industrial personal computer based on a general-purpose personal computer). In this case, the virtualization technology may be used to execute a plurality of OSs (Operating Systems) having different uses in parallel, and to execute necessary applications on each OS.

<B. Relay unit hardware configuration example>
FIG. 3 is a schematic diagram showing a hardware configuration example of a relay unit constituting a control system according to the present embodiment. As shown in FIG. 3, the relay unit 200 has a processor 202 such as a CPU and an MPU (Micro Processing Unit), a chipset 204, a main storage device 206, a secondary storage device 208, and the inside as main components. It includes a bus controller 210, a USB controller 212, a memory card interface 214,

network controllers

216, 218, and an indicator 224.

The processor 202 realizes various communication functions as described later by reading various programs stored in the secondary storage device 208, deploying them in the main storage device 206, and executing the programs. The chipset 204 realizes the processing of the relay unit 200 as a whole by mediating the exchange of data between the processor 202 and each component.

In addition to the system program, the secondary storage device 208 stores various data such as communication setting information that operates in the execution environment provided by the system program.

The internal bus controller 210 is in charge of exchanging data with the control unit 100 and the functional unit 300 via the internal bus.

The USB controller 212 is in charge of exchanging data with an arbitrary information processing device via a USB connection.

The memory card interface 214 is configured so that the memory card 215 can be attached and detached, and data such as a control program and various settings can be written to the memory card 215, or data such as a control program and various settings can be written from the memory card 215. It is possible to read it.

Each of the

network controllers

216 and 218 is in charge of exchanging data with and from any device via the network. The

network controllers

216 and 218 may employ a general purpose network protocol such as Ethernet®. The relay unit 200 communicates with the external device 600 via the network controller 216 and communicates with the external device 700 via the network controller 218.

The indicator 224 notifies the operating state of the relay unit 200, etc., and is composed of one or a plurality of LEDs arranged on the surface of the unit.

FIG. 3 shows a configuration example in which the necessary functions are provided by the processor 202 executing the program, and some or all of these provided functions are provided by a dedicated hardware circuit (for example, ASIC). Alternatively, it may be implemented using an FPGA or the like). Alternatively, the main part of the relay unit 200 may be realized by using hardware that follows a general-purpose architecture (for example, an industrial personal computer based on a general-purpose personal computer). In this case, virtualization technology may be used to execute a plurality of OSs having different uses in parallel, and to execute necessary applications on each OS.

<C. Control system function configuration example>
FIG. 4 is a diagram showing a functional configuration example of the control unit and the relay unit constituting the control system. FIG. 4 shows a functional configuration related to communication between the internal networks NW1, the networks NW2 and NW3, and the external networks NW4 and NW5.

As shown in FIG. 4, the control unit 100 includes a communication unit 14, a DHCP (Dynamic Host Configuration Protocol) server 15, a NAT (Network Address Port Translation) processing unit 16, a setting unit 17, and a storage unit 18. including. The communication unit 14 is realized by the processor 102 shown in FIG. 2,

network controllers

116 and 118, an internal bus controller 122, and the like. The DHCP server 15, the NAT processing unit 16, and the setting unit 17 are realized by the processor 102. The storage unit 18 is realized by the main storage device 106 and the secondary storage device 108.

The storage unit 18 stores the routing table 181 and the conversion data 182. The routing table 181 is a table in which a network identifier that identifies a network is associated with address information (IP address) of a transfer destination of a packet destined for a device connected to the network. The routing table 181 is set by the setting unit 17.

The conversion data 182 is data in which the IP addresses before and after the conversion are associated with each other. The conversion data 182 is temporarily generated by the NAT processing unit 16.

The communication unit 14 controls communication between the internal network NW1 and the networks NW2 and NW3.

For example, the communication unit 14 confirms the destination of the packet received from any of the internal network NW1 and the networks NW2 and NW3. The communication unit 14 reads the IP address corresponding to the confirmed destination network identifier from the routing table 181. The communication unit 14 forwards the packet to the read IP address.

The DHCP server 15 operates as an address assigning unit that assigns an IP address to

ports

11, 22, and 26 connected to the internal network NW1. The DHCP server 15 uses a network identifier that is not used in the network settings of all the units (control unit 100, relay unit 200, and functional unit 300) that make up the control system 1 to IP for

ports

11, 22, and 26. Assign an address.

The NAT processing unit 16 performs NAPT processing between the internal network NW1 and the networks NW2 and NW3. NAPT is a network address translation technology for sharing one IP address among a plurality of terminals. In the NAPT process, the source IP address and port number are translated.

When a packet destined for network NW2 is received from internal network NW1, the NAT processing unit 16 moves the IP address and port number of the packet source to the IP address and unused port number assigned to port 12. Convert to. When a packet destined for the network NW2 is received from the internal network NW1, the NAT processing unit 16 moves the IP address and port number of the packet source to the IP address and unused port number assigned to the port 13. Convert to.

The NAT processing unit 16 generates conversion data 182 in which the IP address and port number before conversion and the IP address and port number after conversion are associated with each other, and stores the generated conversion data 182 in the storage unit 18.

The setting unit 17 sets the routing table 181. The setting unit 17 sets the routing table 181 according to the setting data downloaded from the support device 500. The setting unit 17 stores the set routing table 181 in the storage unit 18. The details of the setting method of the routing table 181 by the setting unit 17 will be described later.

As shown in FIG. 4, the relay unit 200 includes a setting unit 28 and a storage unit 29 in addition to the router 20. The setting unit 28 is realized by the processor 202 shown in FIG. The storage unit 29 is realized by the main storage device 206 and the secondary storage device 208.

The setting unit 28 sets the routing table 25 stored in the storage unit 29. The setting unit 28 sets the routing table 25 according to the setting data downloaded from the support device 500. The setting unit 28 stores the set routing table 25 in the storage unit 29. The details of the setting method of the routing table 25 by the setting unit 28 will be described later.

<D. Screen for network setting of control unit>
FIG. 5 is a diagram showing a screen example for network setting of the control unit. The setting screen 50 illustrated in FIG. 5 is displayed on the support device 500. The support device 500 receives an input from the user for the setting screen 50.

The setting screen 50 has input fields 51 and 52 for setting the IP addresses of the ports 12 and 13, respectively. The user inputs the IP address pre-assigned to the port 12 in the network NW2 into the input field 51, and inputs the IP address pre-assigned to the port 13 in the network NW3 into the input field 52. In the example shown in FIG. 5, the IP address of the port 12 is "192.168.200.1", and the IP address of the port 13 is "192.168.250.1". The network address length of the IP address is 24 bits. Therefore, the network identifier that identifies the network NW2 connected to the port 12 is "192.168.200". The network identifier that identifies the network NW3 connected to the port 13 is "192.168.250".

The setting screen 50 includes input fields 53 and 54 for setting the routing table 181. In the input field 53, a network identifier that identifies the network of the packet destination is input, and in the input field 54, the I address of the packet transfer destination is input. In addition, "255.255.255.0" is set in advance as a subnet mask, and the first 24 bits of the IP address entered in the input field 53 are used as the network identifier.

The setting screen 50 includes a check box 56 for automatically assigning an IP address to a port (

ports

11, 22, 26 in the example shown in FIG. 1) connected to the internal network NW1.

The setting screen 50 includes a check box 57 for executing NAPT processing between the internal network NW1 and the networks NW2 and NW3.

Further, the setting screen 50 includes a check box 58 for executing automatic routing setting to the internal network NW1.

The support device 500 generates setting data according to the input to the setting screen 50. The generated setting data is downloaded to the control unit 100. In the control unit 100, processing according to the setting data is executed. For example, the IP addresses of the ports 12 and 13 are determined according to the input information in the input fields 51 and 52 of the setting screen 50. The setting unit 17 of the control unit 100 adds a record in which the network identifier input in the input field 53 of the setting screen and the IP address input in the input field 54 are associated with the routing table 181. The details of the processing of the control unit 100 when the check boxes 56 to 58 are checked will be described later.

<E. Screen for network setting of relay unit>
FIG. 6 is a diagram showing a screen example for network setting of the relay unit. The setting screen 60 illustrated in FIG. 6 is displayed on the support device 500. The support device 500 receives an input from the user for the setting screen 60.

The setting screen 60 has input fields 61 and 62 for setting the IP addresses of the

ports

23 and 24, respectively. The user inputs the IP address pre-assigned to the port 23 in the external network NW4 into the input field 61, and inputs the IP address pre-assigned to the port 24 in the external network NW5 into the input field 62. In the example shown in FIG. 6, the IP address of the port 23 is “10.0.0.1” and the IP address of the port 24 is “192.168.0.1”. The network address length of the IP address is 24 bits. Therefore, the network identifier that identifies the external network NW4 connected to the port 23 is "10.0.0". The network identifier that identifies the external network NW5 connected to the port 24 is "192.168.0".

The setting screen 60 includes input fields 63 and 64 for setting the routing table 25. A network identifier that identifies the network of the packet destination is input in the input field 63, and an I address of the packet transfer destination is input in the input field 64. Note that "255.255.255.0" is preset as the subnet mask, and the first 24 bits of the IP address entered in the input field 63 are used as the network identifier.

The setting screen 60 includes a check box 65 for executing automatic routing setting to the internal network NW1.

The setting screen 60 includes a check box 66 for setting a VPN (Virtual Private Network) in the external networks NW4 and NW5. When the check box 66 is checked, the setting screen 60 accepts inputs to the input fields 67 to 69. In the input field 67, a pre-common key used for authentication between terminals connected by VPN is input. In the input fields 68 and 69, the user name and password used for authentication at the time of VPN connection are input, respectively. By inputting to the input fields 67 to 69, for example, the relay unit 200 and the external device 600 are connected by VPN.

Furthermore, when the check box 66 is checked, the distribution address to the user is automatically set based on the IP address entered in the input fields 61 and 62. The distributed addresses are displayed in the display fields 70 and 71. As shown in the figure, an IP address having the same network identifier as the IP address of the port 23 is distributed to the external device 600 connected to the external network NW4. An IP address having the same network identifier as the IP address of the port 24 is distributed to the external device 700 connected to the external network NW5.

When the control system 1 includes one or more functional units 300, network settings for one or more functional units 300 are performed using the same setting screen as the setting screen 60 shown in FIG.

<F. Assigning an IP address to a port connected to the internal network>
Next, the process of assigning an IP address to

ports

11, 22, and 26 on the internal network NW1 by the DHCP server 15 will be described. The DHCP server 15 executes the process of assigning an IP address to the

ports

11, 22, and 26 when the check box 56 of the setting screen 50 is checked.

FIG. 7 is a diagram for explaining the process of assigning an IP address to a port on the internal network.

The DHCP server 15 acquires the network identifier and IP address manually set in the network settings using the setting screens 50 and 60 from all the units (control unit 100, relay unit 200, and functional unit 300). The DHCP server 15 assigns a network identifier that is not used in the network settings of all units to the internal network NW1. In the example shown in FIG. 7, "172.16.250" is assigned as the network identifier of the internal network NW1.

The DHCP server 15 assigns an IP address to

ports

11, 22, and 26 on the internal network NW1 using the network identifier. The DHCP server 15 assigns an IP address obtained by combining an arbitrary 8-bit host identifier (host address) with the network identifier (network address) of the internal network NW1 to a port on the internal network NW1 in each unit.

In the example shown in FIG. 7, the DHCP server 15 assigns the IP address “172.162.250.1” to the port 11 of the control unit 100.

Further, the DHCP server 15 assigns a predetermined number (for example, 10) of IP addresses to units (relay unit 200 and functional unit 300) other than the control unit 100. The number of IP addresses assigned to each unit is predetermined in consideration of the number of ports normally possessed by the unit. In the example shown in FIG. 7, the DHCP server 15 assigns 10 IP addresses "172.126.250.10" to "172.12.250.19" to the ports of the relay unit 200. In the example shown in FIG. 1, the relay unit 200 has two

ports

22 and 26 as ports connected to the internal network NW1. Therefore, two IP addresses "172.126.250.10" and "172.12.250.11" out of the ten assigned IP addresses are assigned to the

ports

22 and 26, respectively. Further, when the control system 1 includes one functional unit 300, the DHCP server 15 assigns ten IP addresses "172.126.250.20" to "172.126.250.29" to the ports of the functional unit 300. Assign to.

Note that the DHCP server 15 may inquire each of the relay unit 200 and the functional unit 300 about the number of ports connected to the internal network NW1. The DHCP server 15 may assign each unit an number of IP addresses according to the response. For example, the relay unit 200 answers "two" to the inquiry from the DHCP server 15. In this case, the DHCP server 15 may assign two IP addresses to the relay unit 200.

If the check box 56 on the setting screen 50 is not checked, the IP address may be manually assigned to the port on the internal network NW1.

<G. Routing settings for transferring to the internal network in the control unit>
Next, the routing table automatic setting for transferring to the internal network NW1 in the control unit 100 will be described. The routing table automatic setting is executed by the setting unit 17 of the control unit 100. The setting unit 17 executes the routing table automatic setting when the check box 58 (see FIG. 5) on the setting screen 50 is checked.

FIG. 8 is a diagram illustrating the automatic setting of the routing table for transferring to the internal network in the control unit. The setting unit 17 acquires the IP addresses of the

ports

23 and 24 connected to the external networks NW4 and NW5, respectively, from the relay unit 200. Further, the setting unit 17 acquires the IP address of the port 22 connected to the internal network NW1 in the relay unit 200 assigned by the DHCP server 15.

As shown in FIG. 8, the setting unit 17 adds a record in which the 24-bit network identifier (network address) included in the IP address of the port 23 and the IP address of the port 22 are associated with each other in the routing table 181. The network identifier included in the IP address of port 23 identifies the external network NW4 connected to port 23. Therefore, when the communication unit 14 of the control unit 100 receives a packet destined for the external device 600 connected to the external network NW4, the communication unit 14 transfers the packet to the port 22 of the relay unit 200 based on the routing table 181. Since the network identifier included in the destination of the packet indicates the external network NW4, the router 20 of the relay unit 200 outputs the packet to the external network NW4. As a result, the external device 600 can receive the packet addressed to itself.

Similarly, the setting unit 17 adds a record in which the 24-bit network identifier (network address) included in the IP address of the port 24 is associated with the IP address of the port 22 to the routing table 181. The network identifier included in the IP address of port 24 identifies the external network NW5 connected to port 24. Therefore, when the communication unit 14 of the control unit 100 receives a packet destined for the external device 700 connected to the external network NW5, the communication unit 14 transfers the packet to the port 22 of the relay unit 200 based on the routing table 181. Since the network identifier included in the destination of the packet indicates the external network NW5, the router 20 of the relay unit 200 outputs the packet to the external network NW5. As a result, the external device 700 can receive the packet addressed to itself.

If the check box 58 on the setting screen 50 is not checked, the routing table 181 for transferring to the internal network NW1 may be set manually.

<H. Routing setting for transferring to the internal network in the relay unit>
Next, the routing table automatic setting for transferring to the internal network NW1 in the relay unit 200 will be described. The routing table automatic setting is executed by the setting unit 28 of the relay unit 200. The setting unit 28 executes the routing table automatic setting when the check box 65 (see FIG. 6) on the setting screen 60 is checked.

FIG. 9 is a diagram illustrating the automatic setting of the routing table for transferring to the internal network in the relay unit. The setting unit 28 acquires the IP addresses of the ports 12 and 13 connected to the networks NW2 and NW3 from the control unit 100, respectively. Further, the setting unit 28 acquires the IP address of the port 11 connected to the internal network NW1 in the control unit 100 assigned by the DHCP server 15.

As shown in FIG. 9, the setting unit 28 adds a record in which the 24-bit network identifier (network address) included in the IP address of the port 12 and the IP address of the port 11 are associated with each other in the routing table 25. The network identifier included in the IP address of port 12 identifies the network NW2 connected to port 12. Therefore, when the router 20 of the relay unit 200 receives a packet destined for the support device 500 connected to the network NW2, the router 20 forwards the packet to the port 11 of the control unit 100 based on the routing table 25. Since the network identifier included in the destination of the packet indicates the network NW2, the communication unit 14 of the control unit 100 outputs the packet to the network NW2. As a result, the support device 500 can receive the packet addressed to itself.

Similarly, the setting unit 17 adds a record in which the 24-bit network identifier (network address) included in the IP address of the port 24 is associated with the IP address of the port 22 to the routing table 181. The network identifier included in the IP address of port 24 identifies the external network NW5 connected to port 24. Since the network identifier included in the destination of the packet indicates the network NW3, the communication unit 14 of the control unit 100 outputs the packet to the network NW3. As a result, the device 400 can receive the packet addressed to itself.

If the check box 65 on the setting screen 60 is not checked, the routing table 25 for transferring to the internal network NW1 may be set manually.

<I. NAPT processing>
Next, the NAT processing executed by the control unit 100 will be described. The NAT processing is executed by the NAPT processing unit 16 of the control unit 100. The NAT processing unit 16 executes the NAPT processing when the check box 57 (see FIG. 5) on the setting screen 50 is checked.

FIG. 10 is a diagram illustrating NAPT processing. FIG. 10 shows an example of NAPT processing for a packet addressed to the network NW3 (hereinafter, referred to as a “target packet”). The target packet is a packet whose source is the external device 600 with the IP address "10.0.0.2" and the destination is the device 400 with the IP address "192.168.250.2". The NAT processing unit 16 converts the source IP address and port number of the target packet into the IP address and unused port number of the port 13 connected to the network NW3, respectively. The NAT processing unit 16 generates conversion data 182 in which the IP address and port number before conversion and the IP address and port number after conversion are associated with each other, and stores the generated conversion data 182 in the storage unit 18.

The device 400 that received the target packet transmits a reply packet to the target packet. As described above, the IP address and port number of the source of the target packet are converted into the IP address and the unused port number of the port 13 connected to the network NW3, respectively. Therefore, the device 400 sets the converted IP address and port number as the destination of the reply packet.

When the NAPT processing unit 16 receives a reply packet destined for the converted IP address and port number indicated by the translation data 182 from the network NW3, the NAPT processing unit 16 converts the destination of the reply packet. That is, the NAT processing unit 16 converts the destination of the reply packet into the IP address and port number before conversion indicated by the translation data 182. As a result, the destination IP address of the reply packet is converted to the IP address "10.0.0.2" which is the source of the target packet. As a result, the reply packet is transmitted to the external device 600 having the IP address "10.0.0.2" which is the source of the target packet.

<J. Sequence in automatic network setting>
FIG. 11 is a sequence diagram showing an example of automatic network setting. The network automatic setting shown in FIG. 11 is executed when the

check boxes

56 and 58 are checked on the setting screen 50 of FIG. 5 and the check boxes 65 are checked on the setting screen 60 of FIG.

When the power of the control unit 100 and the relay unit 200 is turned on, the processor 102 of the control unit 100 acquires the configuration information of the relay unit 200 (step S1). The configuration information indicates the model and product number of the relay unit 200. The processor 102 confirms the configuration information of the relay unit 200 (step S2), and starts monitoring the relay unit 200 (step S3). Further, the processor 102 enables the IP addresses of the ports 12 and 13 according to the setting data downloaded from the support device 500 (step S4).

The processor 202 of the relay unit 200 confirms the mounting position (port 22 in the example shown in FIG. 1) with the control unit 100 (step S5). Further, the processor 102 enables the IP addresses of the

ports

23 and 24 according to the setting data downloaded from the support device 500 (step S6).

Next, the processor 202 of the relay unit 200 requests the control unit 100 for the IP address of the port on the internal network NW1 assigned by DHCP (step S7). The processor 102 of the control unit 100 arbitrarily assigns a temporary IP address of each port on the internal network NW1 and distributes the temporary IP address (step S8). In the relay unit 200, the distributed temporary IP address is set (step S9).

The processor 202 of the relay unit 200 establishes an IP connection via the internal network NW1 by using the distributed temporary IP address (step S10). When the IP connection is established, the processor 102 of the control unit 100 transmits the configuration information of the control unit 100 to the relay unit 200 (step S11). The configuration information indicates the model and product number of the control unit 100. The processor 202 of the relay unit 200 confirms the configuration information of the control unit 100 (step S12).

The processor 202 of the relay unit 200 transmits the IP addresses of the

ports

23 and 24 connected to the external networks NW4 and NW5 and the routing table 25 to the control unit 100 (step S13). The IP addresses of

ports

23 and 24 and the routing table 25 are preset in the manual network setting using the setting screen 60 shown in FIG.

When one or more functional units 300 are connected to the control unit 100, the above steps S1 to S13 are also executed for each of the one or more functional units 300.

After step S13, the processor 102 of the control unit 100 assigns a network identifier that is not used in the network settings of all the units to the internal network NW1. Then, the processor 102 determines the IP addresses of all the ports (

ports

11, 22, 26) connected to the internal network NW1 by using the network identifier of the internal network NW1 (step S14). The IP address is assigned by DHCP.

Further, the processor 102 adds a record associated with the network identifier included in each of the IP addresses of the

ports

23 and 24 acquired from the relay unit 200 and the IP address assigned to the port 22 to the routing table 181 (step S15). ).

Next, the processor 102 of the control unit 100 instructs the relay unit 200 to release the temporary IP address (step S16). Further, the processor 102 distributes the official IP address determined in step S14 to the relay unit (step S17). In the relay unit 200, the distributed official IP address is set (step S18).

The processor 202 of the relay unit 200 establishes an IP connection via the internal network NW1 using the distributed formal IP address (step S19). When the IP connection is established, the processor 102 of the control unit 100 transmits information for addition to the routing table 25 to the relay unit 200 (step S20). The information for addition to the routing table 25 includes the network identifiers of the networks NW2 and NW3 connected to the ports 12 and 13, respectively, and the IP address of the port 11. The processor 202 of the relay unit 200 adds a record in which the network identifiers of the networks NW2 and NW3 are associated with the IP address of the port 11 to the routing table 25 (step S21).

After the network automatic setting process is executed in steps S1 to S21, the control unit 100 and the relay unit 200 relay the packets by using the routing tables 181, 25, respectively.

<K. Action / effect>
As described above, the control system 1 is composed of a plurality of units. The plurality of units include a control unit 100 and a relay unit 200. The control unit 100 is connected to the network NW3 and can communicate with the device 400 via the network NW3. The relay unit 200 can communicate with the control unit 100 via the internal network NW1. Further, the relay unit 200 is connected to the external network NW4 and can communicate with the external device 600 via the external network NW4. The control unit 100 has a port 11 connected to the internal network NW1. The relay unit 200 has a port 22 connected to the internal network NW1. The relay unit 200 further includes a router 20 and a setting unit 28. The router 20 relays a packet by using a routing table 25 in which a network identifier that identifies a network and an address information of a forwarding destination of a packet destined for a device connected to the network are associated with each other. The setting unit 28 acquires the network identifier “192.168.250” that identifies the network NW3 from the control unit 100 and the IP address “172.162.250.1” assigned to the port 11. The setting unit 28 sets the acquired network identifier and the IP address in the routing table 25 in association with each other.

According to the above configuration, a record in which the network identifier of the network NW3 and the IP address assigned to the port 11 are associated with each other is automatically added to the routing table 25. Therefore, the trouble of manually setting the network for accessing the device 400 from the external device 600 is reduced.

By using the routing table 25 automatically set in this way, when the router 20 receives a packet destined for the device 400 from the external device 600, the router 20 forwards the packet to the port 11. Since the destination of the packet is the device 400 connected to the network NW3, the control unit 100 outputs the packet from the port 13 to the network NW3. As a result, the device 400 can receive the packet from the external device 600.

The control unit 100 further has a DHCP server 15. The DHCP server 15 assigns IP addresses to

ports

11 and 22 using network identifiers that are not used in the network settings of a plurality of units. As a result, the IP address of the port on the internal network NW1 is automatically assigned. Therefore, the trouble of manually setting the network for accessing the device 400 from the external device 600 is further reduced.

The control unit 100 further includes a communication unit 14 and a setting unit 17. The communication unit 14 relays the packet using the routing table 181. The setting unit 17 sets the network identifier that identifies the external network NW4 and the IP address of the port 22 assigned by the DHCP server 15 in the routing table 181 in association with each other.

According to the above configuration, the network identifier of the external network NW4 and the IP address assigned to the port 22 are associated and automatically set in the routing table 181. Therefore, the trouble of manually setting the network for accessing the external device 600 from the device 400 is reduced.

By using the routing table 181 automatically set in this way, when the communication unit 14 receives a packet destined for the external device 600 from the device 400, the communication unit 14 forwards the packet to the port 22. Since the destination of the packet is the external device 600 connected to the external network NW4, the router 20 of the relay unit 200 outputs the packet from the port 23 to the external network NW4. As a result, the external device 600 can receive the packet from the device 400.

The control unit 100 further has a NAT processing unit 16 for translating the source address and port number of the packet addressed to the network NW3. Thereby, a plurality of external devices 600 can be connected to the device 400 at the same time by using one IP address.

The relay unit 200 and the external device 600 are connected by VPN. As a result, the external device 600 can operate as a device on the internal network NW1.

<L. Addendum>
As described above, the present embodiment includes the following disclosure.

(Structure 1)
A control system (1) composed of a plurality of units (100, 200, 300).
The plurality of units
The first unit (100) connected to the first network (NW2, NW3) and
A second unit (200) capable of communicating with the first unit (100) via the internal network (NW1) and connected to the second network (NW4, NW5) is included.
The first unit (100) has a first port (11) connected to the internal network (NW1).
The second unit (200) has a second port (22) connected to the internal network (NW1).
The second unit (200) further
A router for relaying packets using the first routing table (25) that associates the network identifier that identifies the network with the address information of the forwarding destination of the packet destined for the device connected to the network. 20) and
The first network identifier that identifies the first network (NW2, NW3) and the first address information assigned to the first port (11) are acquired from the first unit (100), and the first network identifier is obtained. A control system having a first setting unit (28) for associating the first address information with the first address information and setting the first address information in the first routing table.

(Structure 2)
The first unit (100) further
The first address information is assigned to the first port (11) by using a network identifier that is not used in the network settings of the plurality of units (100, 200, 300), and the second port (22). The control system (1) according to configuration 1, which has an address allocation unit (15) for assigning a second address information to the device.

(Structure 3)
The first unit (100) further
Communication unit for relaying packets using the second routing table (181) that associates the network identifier that identifies the network with the address information of the forwarding destination of the packet destined for the device connected to the network. (14) and
In order to associate the second network identifier that identifies the second network (NW4, NW5) with the second address information assigned by the address allocation unit (15) and set it in the second routing table (181). The control system (1) according to the configuration 2 having the second setting unit (17) of the above.

(Structure 4)
The first unit (100) further
The control system according to any one of configurations 1 to 3, which has a NAPT (Network Address Port Translation) processing unit (16) for translating the source address and port number of the packet addressed to the first network (NW1). 1).

(Structure 5)
The control system (1) according to any one of configurations 1 to 4, wherein the second unit (200) and the device (600) on the second network are connected by VPN (Virtual Private Network).

(Structure 6)
It is a control method of a control system (1) composed of a plurality of units (100, 200, 300).
The plurality of units
The first unit (100) connected to the first network (NW2, NW3) and
A second unit (200) capable of communicating with the first unit (100) via the internal network (NW1) and connected to the second network (NW4, NW5) is included.
The first unit (100) has a first port (11) connected to the internal network (NW1).
The second unit (200) has a second port (22) connected to the internal network (NW1).
The control method is
The second unit (200) acquires a first network identifier that identifies the first network (NW1) from the first unit (100) and first address information assigned to the first port (11). Then, the step of setting the routing table (25) in which the first network identifier and the first address information are associated with each other, and
A control method in which the second unit (200) includes a step of relaying packets using the routing table (25).

Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is indicated by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

1 controller system, 10 PLC engine, 11-13, 22-24, 26 ports, 14 communication unit, 15 DHCP server, 16 NAPT processing unit, 17, 28 setting unit, 18, 29 storage unit, 20 router, 21 application server. , 25,181 Routine table, 50,60 setting screen, 51-54,61-64,67-69 input field, 56-58,65,66 check box, 70,71 display field, 100 control unit, 102,202 Processor, 104,204 chipset, 106,206 main memory, 108,208 secondary storage, 112,212 USB controller, 114,214 memory card interface, 115,215 memory card, 116,118,216,218 networks Controller, 122,210 internal bus controller, 124,224 indicator, 182 conversion data, 200 relay unit, 300 functional unit, 400 device, 500 support device, 600,700 external device, NW1 internal network, NW2, NW3 network, NW4 NW5 external network.

Claims

A control system consisting of multiple units
The plurality of units
The first unit connected to the first network and
It includes a second unit that can communicate with the first unit via an internal network and is connected to the second network.
The first unit has a first port connected to the internal network.
The second unit has a second port connected to the internal network.
The second unit further
A router for relaying packets using a first routing table that associates a network identifier that identifies a network with the address information of the forwarding destination of packets destined for a device connected to the network.
The first network identifier that identifies the first network and the first address information assigned to the first port are acquired from the first unit, and the first network identifier and the first address information are associated with each other. A control system having a first setting unit for setting in the first routing table.
The first unit further
Address allocation for assigning the first address information to the first port and assigning the second address information to the second port by using a network identifier that is not used in the network settings of the plurality of units. The control system according to claim 1, which has a part.
The first unit further
A communication unit for relaying packets using a second routing table in which a network identifier that identifies a network and an address information of a packet forwarding destination destined for a device connected to the network are associated with each other.
A claim having a second network identifier that identifies the second network and a second setting unit for associating the second address information assigned by the address allocation unit and setting the second address information in the second routing table. 2. The control system according to 2.
The first unit further
The control system according to any one of claims 1 to 3, further comprising a NAPT (Network Address Port Translation) processing unit for translating a source address and a port number of a packet addressed to the first network.
The control system according to any one of claims 1 to 4, wherein the second unit and the device on the second network are connected by VPN (Virtual Private Network).
A control method for a control system consisting of multiple units.
The plurality of units
The first unit connected to the first network and
It includes a second unit that can communicate with the first unit using the internal network and is connected to the second network.
The first unit has a first port connected to the internal network.
The second unit has a second port connected to the internal network.
The control method is
The second unit acquires the first network identifier that identifies the first network from the first unit and the first address information assigned to the first port, and the first network identifier and the first address. Steps to set up a routing table that associates information with
A control method in which the second unit includes a step of relaying packets using the routing table.