Industrial network system
By constructing a coupling group of multiple communication links between the main ring network and the slave ring network, and utilizing media redundancy protocol and probe frame technology, the problem of single ring network disconnection was solved, and high reliability and stable communication of industrial network systems were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SIEMENS (CHINA) CO LTD
- Filing Date
- 2023-03-07
- Publication Date
- 2026-07-10
AI Technical Summary
In industrial production, single-ring network schemes are prone to disconnection due to line faults, which can affect equipment control and production activities.
The system employs a main ring network and at least two slave ring networks, with at least two communication links between each switch. Coupled groups are constructed using a media redundancy protocol. The main switch identifies faulty links through probe frames and switches to backup links to ensure communication continuity.
This effectively avoids single-ring network disconnection, ensuring the stability of equipment control and the continuity of production activities, and reducing communication interruptions caused by single-point failures.
Smart Images
Figure CN116319156B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of industrial networking technology, and in particular to an industrial network system. Background Technology
[0002] Currently, in industrial production, a common networking scheme is a single-ring network with multiple other single-ring networks connected to it. In practical applications of this scheme, line faults often cause the connected single-ring networks to lose connection, resulting in a loss of redundancy. This can lead to abnormalities in the control process of equipment based on this networking scheme, thereby affecting normal production activities. Summary of the Invention
[0003] This invention provides an industrial network system that can reduce or even avoid the occurrence of single-ring network disconnection due to line faults.
[0004] An embodiment of the present invention provides an industrial network system comprising a main ring network and at least two slave ring networks. The main ring network includes at least two first switches, and each slave ring network includes at least two second switches. The number of first switches in the main ring network is the same as the number of second switches in each slave ring network. Each first switch is connected to each second switch in each slave ring network in a one-to-one correspondence. The at least two first switches and the at least two second switches in each slave ring network form a coupling group, such that there are at least two communication links between each first switch and each second switch in each coupling group. When one of the at least two communication links fails, another communication link between the first switch and the second switch in the coupling group can be enabled.
[0005] In one embodiment, in each coupling group, one of the at least two first switches is a master switch, and the other switches in the coupling group are slave switches; wherein:
[0006] Each of the slave switches is used to: send a probe frame to the master switch;
[0007] The master switch is used to: determine whether there is a faulty communication link based on whether it receives probe frames sent by each slave switch in the coupling group, and communicate with the slave switch through other communication links when it is determined that a communication link between a slave switch and the master switch has failed.
[0008] Furthermore, in each coupling group, where a slave switch is the second switch and the master switch and the slave switch have a one-to-one correspondence, the at least two communication links between the master switch and the slave switch include:
[0009] The first communication link directly connects the master switch and the slave switch;
[0010] The second communication link is formed by the master switch, another first switch in the coupling group (excluding the master switch), a second switch in the coupling group that has a one-to-one correspondence with the other first switch, and the slave switch.
[0011] Furthermore, in each coupling group, where a slave switch is the second switch and the master switch and the slave switch are not in a one-to-one correspondence, the at least two communication links between the master switch and the slave switch include:
[0012] The master switch, the first switch which has a one-to-one correspondence with the slave switch, and the third communication link formed by the slave switch;
[0013] The fourth communication link is formed by the master switch, the second switch which has a one-to-one correspondence with the master switch, and the slave switch.
[0014] Furthermore, each probe frame sent from the slave switch includes a switch identifier corresponding to the slave switch and a link identifier corresponding to the communication link used to transmit the probe frame; correspondingly, the master switch is used to: determine the switch identifier in the unreceived probe frames based on the switch identifiers in each received probe frame; determine the faulty communication link based on the link identifiers in each received probe frame; and enable the fault-free communication link for the slave switch corresponding to the switch identifier in the unreceived probe frame.
[0015] In one embodiment, the main ring network is a single ring network constructed by the at least two first switches through interconnection technology based on media redundancy protocol, and the secondary ring network is a single ring network constructed by the at least two second switches through interconnection technology based on media redundancy protocol.
[0016] Furthermore, the at least two first switches and each of the at least two second switches in the ring network form a coupling group through interconnection technology based on a media redundancy protocol.
[0017] In one embodiment, a third switch or firewall is provided on the communication link directly connecting the first switch and the corresponding second switch.
[0018] In one embodiment, the second switch in the slave ring network is connected to a human-machine interaction device so that the slave ring network can access the human-machine interaction device.
[0019] In one embodiment, the main ring network further includes a fourth switch, which is connected to the automation control equipment so that the main ring network can access the automation control equipment.
[0020] The industrial network system provided in this embodiment of the invention, individually or in combination, has at least the following technical effects:
[0021] (1) Since the at least two first switches and the at least two second switches in each of the slave ring networks form a coupling group, there are at least two communication links between each first switch and each second switch in each coupling group. When a communication link between a first switch and a second switch fails, the first switch can communicate with the second switch through other reachable communication links. Therefore, when a communication link fails, only other communication links within the coupling group need to be enabled, ensuring normal communication between the slave ring network and the main ring network where the second switch is located, avoiding the slave ring network from losing connection, i.e., there is no redundancy loss problem. Moreover, the coupling groups constructed in the above manner are independent of each other, and there is no switching from one coupling group to another; the coupling groups do not affect each other. When a communication failure occurs between a main switch and a slave switch within a coupling group, other communication lines within the coupling group can be enabled to ensure normal communication between the main switch and the slave switch within the coupling group, without switching to communication lines in other coupling groups, thus not affecting communication between other slave ring networks and the main ring network.
[0022] (2) In one embodiment, in each coupling group, one of the at least two first switches is the master switch, and the other switches in the coupling group are slave switches, which facilitates the management of the other switches. Moreover, each slave switch in a coupling group sends probe frames to the master switch, enabling the master switch to easily determine whether there is a faulty communication link, and then, when it is determined that a communication link between a slave switch and the master switch is faulty, it can communicate with the slave switch through other communication links.
[0023] (3) In one embodiment, each probe frame sent by a slave switch to the master switch includes a switch identifier and a link identifier. The switch identifier indicates which slave switch the probe frame originates from, and the link identifier indicates which communication link the slave switch uses to send the probe frame. When the master switch does not receive a probe frame from a slave switch in the same coupling group, it indicates that the communication link currently used by that slave switch is faulty. The link identifier can show which communication link is currently being used, thus enabling other normal communication links to be enabled. Therefore, by adding a switch identifier and a link identifier to the probe frame, the master switch can easily identify faulty slave switches and communication links, facilitating the replacement of other communication links for those slave switches. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a schematic diagram of the structure of an industrial network system in one embodiment of the present invention;
[0026] Figure 2 This is a schematic diagram of the structure of an industrial network system in one embodiment of the present invention.
[0027] Figure label:
[0028] M10 Main ring network M21 The first from the ring network M22 The second one is from the ring network. S2, S3 First Switch S4, S5 The first from the second switch in the ring network S6, S7 The second switch from the ring network L1 The communication link directly connecting the first switch S2 and the second switch S4 L2 The communication link directly connecting the first switch S2 and the second switch S6 L3 The communication link directly connecting the first switch S3 and the second switch S5 L4 The communication link directly connecting the first switch S3 and the second switch S7 S8 The third switch between the first switch S2 and the second switch S4 S9 The third switch between the first switch S3 and the second switch S5 D1 Firewall between first switch S2 and second switch S6 D2 Firewall between first switch S3 and second switch S7 H1 The first human-computer interaction device connected from the ring network H2 The second human-computer interaction device connected from the ring network S10 Fourth switch P1 Automated control equipment Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0030] This invention provides an industrial network system.
[0031] The system includes a main ring network and at least two slave ring networks. The main ring network includes at least two first switches, and each slave ring network includes at least two second switches. The number of first switches in the main ring network is the same as the number of second switches in each slave ring network. Each first switch is connected to each second switch in each slave ring network in a one-to-one correspondence. The at least two first switches and the at least two second switches in each slave ring network form a coupling group, so that there are at least two communication links between each first switch and each second switch in each coupling group. When one of the at least two communication links fails, another communication link between the first switch and the second switch in the coupling group can be enabled.
[0032] It is understandable that the above at least two secondary ring networks are subordinate ring networks to the main ring network.
[0033] Understandably, at least two first switches in the main ring network are connected sequentially to form a ring network, and therefore at least two first switches in the main ring network can communicate with each other.
[0034] Understandably, at least two second switches in each ring network are connected sequentially to form a ring network, thus enabling communication between at least two second switches in each ring network.
[0035] Understandably, the number of first switches in the main ring network is the same as the number of second switches in each slave ring network. This facilitates a one-to-one correspondence between each first switch in the main ring network and each second switch in each slave ring network, and enables a one-to-one connection, thereby forming a communication link from each first switch to the corresponding second switch.
[0036] For example, see Figure 1The main ring network M10 has two first switches, S2 and S3. There are two slave ring networks: the first slave ring network M21 includes two second switches, S4 and S5; the second slave ring network M22 includes two second switches, S6 and S7. The second switch S4 in the first slave ring network M21 corresponds to the first switch S2 in the main ring network M10, and they are connected, forming communication link L1 between them. Similarly, the second switch S5 in the first slave ring network M21 corresponds to the first switch S3 in the main ring network M10, and they are connected, forming communication link L3 between them. Finally, the second switch S6 in the second slave ring network M22 corresponds to the first switch S2 in the main ring network M10, and they are connected, forming communication link L2 between them. The second switch S7 in the second ring network M22 and the first switch S3 in the main ring network M10 are corresponding, and the second switch S7 and the first switch S3 are connected to form a communication link L4 between the second switch S7 and the first switch S3.
[0037] It is understood that each of the first switches in the main ring network has a direct communication link with one of the second switches in each of the slave ring networks, and different first switches in the main ring network have direct communication links with different second switches in each of the slave ring networks, that is, there is a one-to-one correspondence between each first switch in the main ring network and each second switch in each slave ring network.
[0038] Understandably, the at least two first switches in the main ring network and the at least two second switches in each of the slave ring networks form a coupled group. See, for example, [link to relevant documentation]. Figure 1 Two coupling groups can be formed: the two first switches S2 and S3 in the main ring network M10 and the two second switches S4 and S5 in the first slave ring network M21. The two first switches S2 and S3 in the main ring network M10 and the two second switches S6 and S7 in the second slave ring network M22.
[0039] Understandably, after a coupling group is formed, there will be at least two communication links between a first switch and a second switch within that coupling group. For example, see... Figure 1There are two communication links between the first switch S2 and the second switch S4. One is the communication link L1 formed by the direct connection between the second switch S4 and the first switch S2. The other communication link is the communication link L3 formed by the direct connection between the second switch S4, the second switch S5, the second switch S5 and the first switch S3, the first switch S3, and the first switch S2.
[0040] Understandably, since there are at least two communication links between a first switch and a second switch, when one communication link fails, the first switch can communicate with the second switch through other reachable communication links. Therefore, when one communication link fails, it is only necessary to switch other communication links within the coupling group, ensuring normal communication between the slave ring network and the main ring network where the second switch is located, avoiding the loss of connection in the slave ring network where the second switch is located, i.e., there is no problem of redundancy loss.
[0041] If the aforementioned coupling group is not formed, and a problem occurs in the communication link between a second switch and a first switch in a slave ring network, the first switch needs to be switched over. After switching the first switch, if the communication link between the second switch in another slave ring network and the switched first switch also fails, the other slave ring network will be disconnected because it cannot switch back. For example, in a scenario where the main ring network M100 has a first slave ring network M21 and a second slave ring network M22 connected to it, the main ring network M10 initially communicates with the first slave ring network M21 and the second slave ring network M22 through the first switch S2. When the communication link L1 between the first switch S2 in the main ring network M10 and the second switch S4 in the first slave ring network M21 fails, the connection will switch from the first switch S2 to the first switch S3. That is, after the switchover, the main ring network M10 communicates with the first slave ring network M21 and the second slave ring network M22 through the first switch S3. If the communication link L4 between the first switch S3 and the second switch S7 also fails, since the communication link L1 between the first switch S2 and the second switch S4 has not yet been restored, the switch cannot be switched from the first switch S3 to the first switch S2. The first switch S3 must continue communicating with the first slave ring network M21 and the second slave ring network M22 respectively. However, due to the failure of the communication link L4 between the first switch S3 and the second switch S7, the main ring network M10 and the second slave ring network M22 cannot communicate normally, and the second slave ring network M22 becomes disconnected.
[0042] A comparison reveals that without a coupling group, there is only one communication link between a second switch and a first switch. Therefore, if this communication link fails, only the first switch can be switched over. However, the industrial network system provided in this embodiment of the invention forms a coupling group, thus providing at least two communication links between a first switch and a second switch. When one communication link fails, the first switch can communicate with the second switch through other reachable communication links without needing to switch over the first switch.
[0043] Understandably, each coupling group is independent of the others; there is no switching from one coupling group to another, and the coupling groups do not affect each other. When a communication failure occurs between a master switch and a slave switch within a coupling group, other communication lines within that coupling group can be used to ensure normal communication between the master switch and the slave switch, without switching to communication lines from other coupling groups.
[0044] In one embodiment, in each coupling group, one of the at least two first switches is a master switch, and the other switches in the coupling group are slave switches; wherein:
[0045] Each of the slave switches is used to: send a probe frame to the master switch;
[0046] The master switch is used to: determine whether there is a faulty communication link based on whether it receives probe frames sent by each slave switch in the coupling group, and communicate with the slave switch through other communication links when it is determined that a communication link between a slave switch and the master switch has failed.
[0047] In other words, in a coupling group, a first switch is designated as the master switch, and the other first switches and each second switch in the coupling group are slave switches.
[0048] For example, see Figure 1In the coupled group formed by the first switch S2 and S3 and the second switches S4 and S5, the first switch S2 is the master switch, and the first switch S3, second switch S4, and second switch S5 are slave switches. At this time, the first switch S2 acts as the master manager, and the first switch S3, second switch S4, and second switch S5 act as clients. In this coupled group, the initial communication links for each slave switch to send probe frames are: first switch S3 → first switch S2; second switch S4 → first switch S2; second switch S5 → first switch S3 → first switch S2. If the master switch S2 receives probe frames from all three slave switches S3, S4, and S5, it indicates that the three initial communication links are normal. If it only receives probe frames from slave switches S3 and S4, it indicates that the communication link of slave switch S5: second switch S5 → first switch S3 → first switch S2 is faulty. Since the communication link between first switch S3 and first switch S2 is not faulty, the communication link between second switch S5 and first switch S3 is faulty. At this point, the communication line for the second switch S5 is changed, for example, to the second switch S5 → second switch S4 → first switch S2.
[0049] Understandably, in a coupled group, only one primary switch acts as the master switch, and the other switches act as slave switches, which facilitates the management of the other switches.
[0050] Furthermore, in each coupling group, where a slave switch is the second switch and the master switch and the slave switch have a one-to-one correspondence, the at least two communication links between the master switch and the slave switch include:
[0051] The first communication link directly connects the master switch and the slave switch;
[0052] The second communication link is formed by the master switch, another first switch in the coupling group (excluding the master switch), a second switch in the coupling group that has a one-to-one correspondence with the other first switch, and the slave switch.
[0053] For example, see Figure 1 The slave switch S4 and the master switch S2 are in a one-to-one correspondence and connected relationship. For the slave switch S4, the first communication link in the communication line between the slave switch S4 and the master switch S2 is master switch S2 → slave switch S4, and the second communication link is: master switch S2 → slave switch S3 → slave switch S5 → slave switch S4.
[0054] Furthermore, in each coupling group, where a slave switch is the second switch and the master switch and the slave switch are not in a one-to-one correspondence, the at least two communication links between the master switch and the slave switch include:
[0055] The master switch, the first switch which has a one-to-one correspondence with the slave switch, and the third communication link formed by the slave switch;
[0056] The fourth communication link is formed by the master switch, the second switch which has a one-to-one correspondence with the master switch, and the slave switch.
[0057] For example, see Figure 1 The relationship between switch S5 and master switch S2 is not one-to-one. For switch S5, the third communication link in the communication line between switch S5 and master switch S2 is master switch S2 → switch S3 → switch S5; the fourth communication link is master switch S2 → switch S4 → switch S5.
[0058] Furthermore, each probe frame sent from the slave switch includes a switch identifier corresponding to the slave switch and a link identifier corresponding to the communication link used to transmit the probe frame; correspondingly, the master switch is used to: determine the switch identifier in the unreceived probe frames based on the switch identifiers in each received probe frame; determine the faulty communication link based on the link identifiers in each received probe frame; and enable the fault-free communication link for the slave switch corresponding to the switch identifier in the unreceived probe frame.
[0059] In other words, each probe frame sent from a slave switch to the master switch includes a switch identifier and a link identifier. The switch identifier indicates which slave switch the probe frame originated from, and the link identifier indicates which communication link the slave switch used to send the probe frame. When the master switch does not receive a probe frame from a slave switch in the same coupling group, it indicates that the communication link currently used by that slave switch is faulty. The link identifier can reveal which communication link is currently being used, thus allowing other normal communication links to be activated.
[0060] As can be seen, by adding switch and link identifiers to the probe frames, the master switch can easily identify abnormal slave switches and communication links, thus facilitating the replacement of other communication links for the slave switch.
[0061] In one embodiment, the main ring network is a single ring network constructed by the at least two first switches through interconnection technology based on media redundancy protocol, and the secondary ring network is a single ring network constructed by the at least two second switches through interconnection technology based on media redundancy protocol.
[0062] Medium Redundancy Protocol (MRP) is the English name for this protocol. Interconnection technology based on MRP refers to interconnection technology based on MRP, and can also be called MRP interconnection technology.
[0063] Understandably, since the main ring network is constructed by interconnecting at least two first switches using MRP technology, the main ring network is an MRP ring network. Similarly, the secondary ring network is also an MRP ring network, satisfying the millisecond-level network self-healing architecture.
[0064] In one embodiment, the at least two first switches and each of the at least two second switches in the ring network form a coupling group through interconnection technology based on a media redundancy protocol.
[0065] Since both the main ring network and the slave ring network are constructed based on MRP interconnection technology, they can form coupled groups based on MRP interconnection technology. Compared with standby coupling technology, MRP interconnection technology can reduce overall coupled line errors caused by single-point failures. Standby coupling technology is a waiting coupling technology.
[0066] In one embodiment, a third switch or firewall is provided on the communication link directly connecting the first switch and the corresponding second switch.
[0067] In real-world scenarios, it is often necessary to add a new switch or firewall between the first and second switches. For distinction, this additional switch between the first and second switches is referred to as the third switch. See also Figure 2 A third switch S8 was added between the first switch S2 and the second switch S4; a third switch S9 was added between the first switch S3 and the second switch S5; a firewall D1 was added between the first switch S2 and the second switch S6; and a second firewall D2 was added between the first switch S3 and the second switch S7.
[0068] In an embodiment of the present invention, see Figure 2If the communication link directly connecting the third switch S8 and the second switch S4 fails, the second switch S4 will communicate with the first switch S2 through other communication links, for example, second switch S4-second switch S5-first switch S3-first switch S2. If the communication link directly connecting the first switch S2 and the second switch S6 also fails, the second switch S6 can communicate with the first switch S2 through other communication links, for example, second switch S6-second switch S7-first switch S3-first switch S2.
[0069] Understandably, if no coupling group is formed, and the communication link directly connecting the third switch S8 and the second switch S4 fails, the first switch S2 will not be aware of the problem and will not switch to the first switch S3. Therefore, the first slave ring network M21 will lose connection. Next, if the communication link between firewall D1 and the second switch S6 also fails, the first switch S2 will again be unaware of the problem, causing the second slave ring network M22 to lose connection. Thus, when a firewall or switch is added to a link, a problem in the communication link between the new device and the second switch will cause the slave ring network containing that second switch to lose connection.
[0070] In contrast, since a coupling group is formed in the embodiment of the present invention, when a device is added between the first switch and the second switch, if a problem occurs in the communication link between the newly added device and the second switch, it will not cause the secondary ring network where the second switch is located to lose connection, thus ensuring normal communication.
[0071] As can be seen, the industrial network system provided in this embodiment of the invention allows the deployment of hardware devices, namely the aforementioned third switch and firewall, on the coupled lines. In practical scenarios, the processing priority of control data from automated control equipment can be fully guaranteed by reasonably setting the virtual LAN configuration parameters of the third switch and firewall devices.
[0072] In one embodiment, the second switch in the slave ring network is connected to a human-machine interaction device so that the slave ring network can access the human-machine interaction device.
[0073] In other words, a human-machine interface (HMI) device can be connected to the second switch in the ring network, thus enabling the ring network to access HMI devices. Besides HMI devices, other devices can also be connected, such as input / output devices, cameras, etc. Devices that need to be connected to the network environment can be added according to the actual needs of the site.
[0074] See Figure 2The second switch S4 is connected to the human-machine interface device H1, enabling the first device from ring network M21 to access the human-machine interface device. The second switch S7 is connected to the human-machine interface device H2, enabling the second device from ring network M22 to access the human-machine interface device.
[0075] In one embodiment, see Figure 2 The main ring network M10 also includes a fourth switch S10, which is connected to the automation control device P1 so that the main ring network M10 can access the automation control device P1.
[0076] In other words, in addition to at least two primary switches participating in the formation of the coupling group, the main ring network also includes a fourth switch. This fourth switch connects to automatic control equipment, such as a programmable logic controller (PLC). The automatic control equipment can control the production activities of production equipment in the field environment.
[0077] For example, in one scenario, a user issues control commands through a human-machine interface device connected to a second switch in a secondary ring network. The control commands are then sent through the secondary ring network to a first switch in the primary ring network. The first switch then forwards the control commands to a fourth switch, which in turn sends the control commands to a programmable logic controller (PLC). This enables the PLC to control the production activities on-site according to the user's control commands.
[0078] Understandably, the industrial network system provided in this invention has high reliability and can solve the problem of multi-ring network coupling redundancy switching in a ring network composed of automated control equipment and industrial switching equipment. Different coupling groups work independently, allowing each slave ring network to communicate independently with the main ring network. A third switch or firewall can be deployed. In the event of a single point of physical line failure, it does not affect its own ring network and coupling redundancy requirements, nor does it affect the switching problems of other ring networks. The industrial network system provided in this invention can be applied to operational technology network systems with stringent requirements for data transmission real-time performance and redundancy, and belongs to the field of industrial wired communication technology.
[0079] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.
[0080] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of the present invention should be included within the scope of protection of the present invention.
Claims
1. An industrial network system, characterized in that, The system includes a main ring network and at least two slave ring networks. Each main ring network includes at least two first switches, and each slave ring network includes at least two second switches. The number of first switches in the main ring network is the same as the number of second switches in each slave ring network. Each first switch is connected one-to-one with each second switch in each slave ring network. The at least two first switches and the at least two second switches in each slave ring network form a coupling group, such that there are at least two communication links between each first switch and each second switch in each coupling group. If one of the at least two communication links fails, another communication link between the first switch and the second switch in the coupling group can be activated. In each coupling group, one of the at least two first switches is the master switch, and the other switches in the coupling group are slave switches. In each coupling group, where a slave switch is the second switch and the master switch and the slave switch have a one-to-one correspondence, the at least two communication links between the master switch and the slave switch include: The first communication link directly connects the master switch and the slave switch; The second communication link is formed by the master switch, another first switch in the coupling group (excluding the master switch), a second switch in the coupling group that has a one-to-one correspondence with the other first switch, and the slave switch. In each coupling group, where a slave switch is the second switch and the master switch and the slave switch are not in a one-to-one correspondence, the at least two communication links between the master switch and the slave switch include: The master switch, the first switch which has a one-to-one correspondence with the slave switch, and the third communication link formed by the slave switch; The fourth communication link is formed by the master switch, the second switch which has a one-to-one correspondence with the master switch, and the slave switch.
2. The system according to claim 1, characterized in that, Each of the slave switches is used to: send a probe frame to the master switch; The master switch is used to: determine whether there is a faulty communication link based on whether it receives probe frames sent by each slave switch in the coupling group, and communicate with the slave switch through other communication links when it is determined that a communication link between a slave switch and the master switch has failed.
3. The system according to claim 2, characterized in that, Each probe frame sent from the slave switch includes a switch identifier corresponding to the slave switch and a link identifier corresponding to the communication link used to transmit the probe frame; correspondingly, the master switch is used to: determine the switch identifier in the unreceived probe frames based on the switch identifiers in each received probe frame; determine the faulty communication link based on the link identifiers in each received probe frame; and enable the fault-free communication link for the slave switch corresponding to the switch identifier in the unreceived probe frame.
4. The system according to claim 1, characterized in that, The main ring network is a single ring network constructed by the interconnection technology of the at least two first switches based on the media redundancy protocol, and the secondary ring network is a single ring network constructed by the interconnection technology of the at least two second switches based on the media redundancy protocol.
5. The system according to claim 4, characterized in that, The at least two first switches and each of the at least two second switches in the ring network form a coupling group through interconnection technology based on media redundancy protocol.
6. The system according to claim 1, characterized in that, A third switch or firewall is installed on the communication link directly connecting the first switch and the corresponding second switch.
7. The system according to claim 1, characterized in that, The second switch in the slave ring network is connected to the human-machine interaction device so that the slave ring network can access the human-machine interaction device.
8. The system according to claim 1, characterized in that, The main ring network also includes a fourth switch, which is connected to the automation control equipment so that the main ring network can access the automation control equipment.