Industrial Ethernet ring redundancy communication system and method

Abstract

The invention discloses an industrial Ethernet ring redundancy communication system and method, the system comprises a main control station and at least one remote station, the main control station comprises a controller, a first exchange chip, a first expansion communication unit and at least one first communication or I / O unit, the controller, the first expansion communication unit and the at least one first communication or I / O unit are respectively connected with the first switch chip, and two ports of the first expansion communication unit are connected with the first switch chip; the at least one remote station comprises a second switch chip, a second expansion communication unit and at least one second communication or I / O unit, the second expansion communication unit and the at least one second communication or I / O unit are respectively connected with the second switch chip, and two ports of the second expansion communication unit are connected with the second switch chip; and the first expansion communication unit and the second expansion communication unit communicate with each other.

Description

Technical Field

[0001] This invention relates to the field of industrial automation technology, and in particular to an industrial Ethernet ring redundant communication system and method. Background Technology

[0002] In industrial control systems, such as DCS or PLC, industrial Ethernet is increasingly used between the main controller and remote I / O modules / communication modules. Most systems employ a simple, low-cost bus topology. With the continuous development of industry, the requirements for the reliability and stability of control systems are becoming increasingly stringent. Currently, many large-scale control systems are converting linear bus topologies to ring topologies to improve network availability, supporting ring redundancy networks. For example, the patent "A Redundant System with Dual-Ring Network Links" achieves controller redundancy and network redundancy. Each communication module in each expansion rack of the system is redundantly designed to prevent the control system from stopping operation when facing multiple different levels of failure. Furthermore, both communication and I / O modules support hot-swapping, allowing redundant modules to ensure normal system operation during system maintenance. Another example is the patent "A High-Speed ​​Bus Network Based on Switching and Ring Network Redundancy," which provides a high-speed bus network based on switching and ring network redundancy to address the requirements of future avionics systems for data volume, real-time performance, and reliability. Yet another example is "An Industrial Ethernet Fast Redundancy Method," which provides a simple and fast switching method for industrial Ethernet, increasing the switching speed of the ring network to 100ms. The patent "Industrial PLC Equipment and Ring Network System" provides an industrial PLC equipment and ring network system to solve the problems of long switching time and complex deployment of industrial Ethernet in the prior art.

[0003] However, the above technical solution has the following problems: 1. Ring topologies based on industrial Ethernet require redundant switching and data recovery time, which can be tens of milliseconds or even 100 milliseconds, affecting the continuity of data communication and the stable operation of the system. 2. In the design of ring redundancy, although the physical topology is ring, not both rings actually carry data, resulting in low data reliability. Summary of the Invention

[0004] Based on the above-mentioned technical problems, this invention proposes an industrial Ethernet ring redundant communication system and method to solve the problems of poor data communication continuity, unstable system operation, and low data reliability in the prior art.

[0005] To achieve the above objectives, according to one aspect of the present invention, an industrial Ethernet ring redundant communication system is proposed, comprising a master control station and at least one remote station. The main control station includes a controller, a first switching chip, a first extended communication unit, and at least one first communication or I / O unit. The controller, the first extended communication unit, and the at least one first communication or I / O unit are respectively connected to the first switching chip. The two ports of the first extended communication unit are connected to the first switching chip. At least one remote station includes a second switching chip, a second extended communication unit, and at least one second communication or I / O unit. The second extended communication unit and the at least one second communication or I / O unit are respectively connected to the second switching chip. Two ports of the second extended communication unit are connected to the second switching chip. The first extended communication unit and the second extended communication unit communicate with each other.

[0006] Optionally, the controller occupies one communication interface of the first switching chip, the at least one first communication or I / O unit occupies one communication interface of the first switching chip, and the first extended communication unit occupies two communication interfaces of the first switching chip.

[0007] Optionally, the at least one second communication or I / O unit occupies one communication interface of the second switching chip, and the second extended communication unit occupies two communication interfaces of the second switching chip.

[0008] Optionally, the first extended communication unit and the second extended communication unit communicate via optical fiber or cable.

[0009] Optionally, the first extended communication unit and the second extended communication unit include an S1 port, an S2 port, an Up port, and a Down port. The S1 port and S2 port of the first extended communication unit are respectively connected to the two communication interfaces of the first switching chip; The S1 and S2 ports of the second extended communication unit are connected to the two communication interfaces of the second switching chip.

[0010] Optionally, the first extended communication unit and the second extended communication unit adopt FPGA logic design, and the MAC layer of the data is packaged internally by the FPGA.

[0011] Optionally, the S1 port and Up port of the first extended communication unit and the second extended communication unit are in one group, and the S2 port and Down port are in another group, and all ports are connected to the PHY chip.

[0012] Optionally, the first extended communication unit and the second extended communication unit include a message judgment subunit. The message judgment subunit determines whether the destination address of a message entering through port S1 or port S2 is this station. If it is not this station, it forwards the message; if it is this station, it discards the message. The message judgment subunit determines whether the source address of a message entering through the Up port or Down port is the local station. If it is not the local station, it is forwarded; if it is the local station, it is discarded.

[0013] Optionally, there is at least one controller, and when there are two controllers, the two controllers are mutually redundant, with one being the master and the other the slave.

[0014] To achieve the above objectives, according to another aspect of the present invention, an industrial Ethernet ring redundancy communication method is proposed. This method is applied to the industrial Ethernet ring redundancy communication system described in the preceding embodiment, and includes: When the controller sends a message to the station's I / O, the message is sent directly to the communication or I / O unit through the station's switching chip. The extended communication unit intercepts the message and does not send the message to the remote station. When the controller sends a message to the remote station IO, the message is broadcast through the station's switching chip, and two copies of the message are sent to the remote station IO through the two ports of the extended communication unit. The message is then sent to the target IO unit of the remote station through two communication loops. When the station's internal I / O sends a message to the controller, the message is sent directly to the controller through the station's switching chip. The extended communication unit intercepts the message and does not send the message to the remote station. When the remote station IO sends a message to the controller, the message is broadcast through the remote station's switching chip, and two copies of the message are sent to the controller through the two ports of the remote station's extended communication unit, and then sent to the controller through two communication loops respectively.

[0015] Based on the above technical solution, the present invention has at least the following beneficial effects: A highly reliable, seamless, redundant ring network structure based on industrial Ethernet is employed. A parallel data transmission mechanism is designed within the ring redundancy, eliminating the need for switching in the event of a network failure in single-redundant ring links between remote stations, providing a 0-millisecond recovery time. Dual-ring communication and dual-data backup enhance the reliability of data communication in the ring redundancy topology. Attached Figure Description

[0016] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of an industrial Ethernet ring redundant communication system according to one embodiment of this application; Figure 2 This is a ring-redundant physical topology diagram of one embodiment of this application; Figure 3 This is a network architecture diagram of one embodiment of this application; Figure 4 This is a schematic diagram of the data flow from the CPU to the local station's communication or I / O unit in one embodiment of this application; Figure 5 This is a schematic diagram of the data flow from the CPU to the communication or I / O unit of a remote station according to one embodiment of this application; Figure 6 This is a schematic diagram of the data flow from the communication or I / O unit of this station to the CPU in one embodiment of this application; Figure 7 This is a schematic diagram of the data flow from the communication or I / O unit of a remote station to the CPU in one embodiment of this application; Figure 8 This is a schematic diagram of an extended communication unit of a remote station according to one embodiment of this application; Figure 9 This is a schematic diagram of a redundant ring network architecture according to one embodiment of this application. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0019] Example To address the problems of poor data communication continuity, system instability, and low data reliability in existing technologies, this invention proposes a software testing task scheduling method and apparatus.

[0020] According to one aspect of the present invention, an industrial Ethernet ring redundant communication system is proposed, such as... Figure 1 As shown, it includes a main control station 100 and at least one remote station 200.

[0021] The main control station 100 includes a controller 110, a first switching chip 120, a first extended communication unit 130, and at least one first communication or I / O unit 140. The controller 110, the first extended communication unit 130, and the at least one first communication or I / O unit 140 are each connected to the first switching chip 120. Two ports of the first extended communication unit 130 are connected to the first switching chip 120. Specifically, the controller 110 occupies one communication interface of the first switching chip 120, the at least one first communication or I / O unit 140 occupies one communication interface of the first switching chip 120, and the first extended communication unit 130 occupies two communication interfaces of the first switching chip 120.

[0022] At least one remote station 200 includes a second switching chip 210, a second extended communication unit 220, and at least one second communication or I / O unit 230. The second extended communication unit 220 and the at least one second communication or I / O unit 230 are respectively connected to the second switching chip 210, and two ports of the second extended communication unit 220 are connected to the second switching chip 210. Specifically, the at least one second communication or I / O unit 230 occupies one communication interface of the second switching chip 210, and the second extended communication unit 220 occupies two communication interfaces of the second switching chip 210.

[0023] The first extended communication unit 130 and the second extended communication unit 220 communicate with each other. Specifically, the first extended communication unit 130 and the second extended communication unit 220 can communicate via optical fiber or cable.

[0024] In one embodiment of this application, the first extended communication unit 130 and the second extended communication unit 220 are identical extended communication units, both including an S1 port, an S2 port, an Up port, and a Down port. The S1 port and S2 port of the first extended communication unit 130 are respectively connected to two communication interfaces of the first switching chip 120. The S1 port and S2 port of the second extended communication unit 220 are connected to two communication interfaces of the second switching chip 210. Specifically, the S1 port and Up port of the first extended communication unit 130 and the second extended communication unit 220 form one group, and the S2 port and Down port form another group; all ports are connected to the PHY chip.

[0025] In one embodiment of this application, the first extended communication unit 130 and the second extended communication unit 220 are designed using FPGA logic, and the FPGA internally completes the MAC layer packaging of the data.

[0026] In one embodiment of this application, the first extended communication unit 130 and the second extended communication unit 220 include a message judgment subunit. The judgment logic of the message judgment subunit is as follows: 1: Determine whether the destination address of a message entering through port S1 or port S2 is the local station. If it is not the local station, forward it; if it is the local station, discard it. 2: Determine whether the source address of a message entering through port Up or port Down is the local station. If it is not the local station, forward it; if it is the local station, discard it.

[0027] In one specific embodiment of the present invention, there is at least one controller 110. When there are two controllers 110, the two controllers are mutually redundant, acting as master and slave to each other.

[0028] To achieve the above objectives, another aspect of the present invention proposes an industrial Ethernet ring redundancy communication method. This method is applied to the industrial Ethernet ring redundancy communication system described in the preceding embodiment, and includes the following steps: S1, when the controller sends a message to the station's I / O, the message is sent directly to the communication or I / O unit through the station's switching chip. The extended communication unit intercepts the message and does not send the message to the remote station.

[0029] S2, when the controller sends a message to the remote station IO, the message is broadcast through the station's switching chip, and two copies of the message are sent to the remote station IO through the two ports of the extended communication unit, and then sent to the target IO unit of the remote station through two communication loops respectively.

[0030] S3: When the station's internal IO sends a message to the controller, the message is sent directly to the controller through the station's switching chip. The extended communication unit intercepts the message and does not send the message to the remote station.

[0031] S4. When the remote station IO sends a message to the controller, the message is broadcast through the switching chip of the remote station. Two copies of the message are sent to the controller through the two ports of the extended communication unit of the remote station, and then sent to the controller through two communication loops respectively.

[0032] Based on the above technical solution, the present invention has at least the following beneficial effects: A highly reliable, seamless, redundant ring network structure based on industrial Ethernet is employed. A parallel data transmission mechanism is designed within the ring redundancy, eliminating the need for switching in the event of a network failure in single-redundant ring links between remote stations, providing a 0-millisecond recovery time. Dual-ring communication and dual-data backup enhance the reliability of data communication in the ring redundancy topology.

[0033] The following describes in detail an industrial Ethernet ring redundant communication system and its communication method using a specific embodiment.

[0034] The ring-redundant physical topology of the present invention, such as Figure 2 As shown, it consists of one main control station and N remote stations. The main control station includes a controller, an extended communication unit, an industrial communication interface unit, and I / O units. The remote stations, unlike the main control station, do not have a controller, but their other units are the same as the main controller.

[0035] The controller is the main processor. Generally, each master control station in a PLC or DCS system contains at least one controller. Both the controller and the ring network can support backup redundancy, meaning two controllers can act as master and slave to each other, with two redundant ring network links for communication. For simplicity, this invention only describes one of the redundant ring network architectures.

[0036] The extended communication unit primarily enables the expansion of the main control station and remote stations. Typical control systems require multiple remote stations (extension racks) to accommodate remote deployments and larger point scales.

[0037] The industrial communication interface unit is used to convert industrial communication networks for communication with devices that support other standard industrial protocols, including CANOpen, RS, Profibus, etc.

[0038] I / O units include analog and digital inputs and outputs.

[0039] A ring topology refers to an extended communication unit connected end to end to form a communication loop. Even if the communication link (fiber optic cable or network cable) fails, the controller can still communicate normally with the industrial communication interface unit and I / O unit.

[0040] The network architecture of this invention, such as Figure 3 As shown, the main control station consists of one baseboard, and each remote station also has its own baseboard. Each baseboard contains a switch chip. The CPU (controller) occupies one communication port on the switch chip; each communication or I / O unit occupies one communication port on the switch chip; and the expansion communication unit occupies two communication ports on the switch chip. The wiring within the station represents the wiring within the baseboard, while the connections between the various expansion communication units are external fiber optic cables or electrical cables.

[0041] The CPU periodically sends data to each communication or I / O unit on the baseboard of the main control station and / or the baseboard of the remote station, and each communication or I / O unit replies with data to the CPU.

[0042] The extended communication unit is responsible for data interaction and performs ring redundancy judgment, cutting off loop data.

[0043] Specifically, the data flow of this invention is as follows: A: Communication or I / O unit from the CPU to this station like Figure 4As shown, the data packet is sent directly to the communication or I / O unit via the switching chip. Simultaneously, the switching chip transmits both data streams to an external station via the port of the extended communication unit. The extended communication unit then truncates the data packet, preventing it from being transmitted to other backplanes (remote stations).

[0044] B: CPU-to-remote station communication or I / O unit like Figure 5 As shown, the switching chip broadcasts data packets and sends two data packets to other remote stations through two ports of the extended communication unit, forming two data streams. Data stream A enters the switching chip sequentially through extended communication unit m and extended communication unit R1, reaching the target communication or I / O unit of the remote station; data stream B enters the switching chip sequentially through extended communication unit m, extended communication unit Rn, and extended communication unit R1, and the switching chip distributes the data packets to the target communication or I / O unit.

[0045] C: Communication or I / O unit of this station to CPU like Figure 6 As shown, the communication or I / O unit sends data packets directly to the CPU via the switching chip. Simultaneously, the switching chip transmits both data streams to an external station via the port of the extended communication unit. The extended communication unit then truncates the data packet, preventing its transmission to other backplanes (remote stations).

[0046] D: Communication or I / O unit of remote station to CPU like Figure 7 As shown, the switching chip broadcasts data packets, sending two data packets to other stations through two ports of the extended communication unit, forming two data streams. Data stream A passes through extended communication unit R1 and extended communication unit m in sequence, enters the switching chip of the main control station, and reaches the CPU; data stream B passes through extended communication unit R1, extended communication unit Rn, and extended communication unit m in sequence, enters the switching chip of the main control station, and is finally sent to the CPU.

[0047] In summary, when a remote station's communication or I / O unit communicates with the CPU, two data streams are generated and transmitted in parallel. A single point of failure in the external communication link between different stations will not affect data transmission.

[0048] The following describes the communication mechanism between the controller CPU and the communication or I / O unit.

[0049] The CPU communicates with communication or I / O units in a question-and-answer format. The CPU sends data packets to the communication or I / O unit, and the communication or I / O unit responds to the CPU with a reply packet upon receiving the packet. Because switched Ethernet technology is used, communication between the CPU and multiple communication or I / O units is not sequential. Instead of waiting for a reply from one communication or I / O unit before sending to the next, the CPU sends a packet to the next communication or I / O unit immediately after sending the current one. The entire CPU then waits for replies from all communication or I / O units. After a specified time has elapsed, the next round of communication is initiated.

[0050] The communication messages use the standard Ethernet protocol and conform to the IEEE 802.3 protocol. The data frame format is shown in Table 1: Table 1 Among them, the preamble is the beginning of the data frame; the start delimiter marks the beginning of the destination address of the data frame; the MAC destination address refers to the MAC address of the destination node receiving the data frame; the MAC source address refers to the MAC address of the source node sending the data frame; the message type is used to indicate the detailed type of the data packet, such as periodic message, non-periodic message (reset, calibration, etc.); and FCS is the Ethernet frame check sequence.

[0051] MAC address convention: Both the source and destination MAC addresses contain station number and slot number information. The MAC address is a crucial basis for packet filtering. The specific format is shown in Table 2.

[0052] Table 2 The mechanism by which the switching chip processes data is as follows: The switching chip forwards data received at each port to other ports. The design employs a broadcast processing method, where data received at each port is forwarded to other ports.

[0053] The processing mechanism for the extended communication unit is as follows: The extended communication unit's function is to communicate with extended remote stations, analyze the address of each data packet, and cut off loop data. Specifically, the extended communication unit has four ports: two are connected to the switching chip via the backplane and are defined as S1 and S2 respectively; the other two are external communication interfaces, defined as Up and Down ports respectively, which connect to different stations via external cables. The extended communication unit needs to identify the station number to which this module belongs.

[0054] The extended communication unit and the receiving port of the switching chip are S1 / S2. After receiving a data packet, the extended communication unit determines the destination address of the packet. If the station number in the destination address is the same as the station number of the extended communication unit itself, it indicates that the packet is a communication packet between the local CPU and the local I / O, and the packet is not forwarded. Otherwise, it is forwarded normally.

[0055] The extended communication unit's interface with external communication is Up / Down. Upon receiving a data packet, the extended communication unit determines the packet's source address. If the station number in the source address matches the extended communication unit's own station number, it indicates that the packet is a loopback packet and will be discarded and not forwarded when resent to this station. Otherwise, it is forwarded normally.

[0056] The four ports of the extended communication unit are divided into two groups. Each group contains one connection port to the switching chip and one interface for external communication. During data packet forwarding, only the two interfaces within the same group forward data to each other.

[0057] The CPU and communication / I / O units will receive two identical data packets, each containing a sequence number field. Upon receiving a packet, the CPU or I / O unit first determines if it is destined for itself; if not, it discards the packet. If it is, it further checks the sequence number. If a packet with the same sequence number has already been processed, the later received packet is discarded.

[0058] The switching chip uses FPGA logic design, broadcasting received packets from each port to other ports. The switching chip can also be implemented using a Layer 2 switching chip or a dedicated switching chip. Each port of the switching chip needs to be configured as a mirror port, or the MAC address needs to be set as a broadcast address. The station number and slot number fields should be defined at the application layer to distinguish the destination address of the packet.

[0059] The design scheme for the extended communication unit can be as follows: Figure 8 As shown.

[0060] Specifically, the extended communication unit adopts an FPGA design, with S1 and Up ports forming one group, and S2 and Down ports forming another group. Each port is directly connected to the PHY chip, and the MAC layer packaging of the data is completed internally within the FPGA.

[0061] The system comprises several components: a data receiving unit, a data sending unit, and a data receiving unit. The receiving unit receives data packets from the port, buffers them, and performs verification. The data sending unit buffers the data packets to be sent, packages them at the MAC layer, and then sends them. The packet judgment unit judges each received packet based on its MAC address. For ports S1 and S2, it determines the destination address of the packet; if the destination address is the local station, it discards the packet; otherwise, it forwards it normally and writes the data packet into the data sending unit. For ports Up and Down, it determines the source address of the packet; if the source address is the local station, it discards the packet; otherwise, it forwards it normally.

[0062] In one specific embodiment, a redundant ring network architecture can be as follows: Figure 9 As shown.

[0063] CPU: Main processing unit. A main processing unit is typically configured in the main control station of an industrial control system (DCS) or PLC.

[0064] CCU Unit: The functions of the switching chip and the aforementioned extended communication unit are implemented using an FPGA.

[0065] CAN communication, RS communication unit and I / O unit: All three units act as slave nodes of the CPU and communicate with the CPU periodically.

[0066] Dual-core fiber optic communication is used to extend communication between different remote stations. A single-ring network enables redundant dual-ring communication for data loops.

[0067] The technical solution of this invention is based on a highly reliable, seamless, redundant ring network structure of industrial Ethernet. A parallel data transmission mechanism is designed within the ring redundancy. For single-redundant ring links between remote stations, no switching is required in the event of a network failure, providing a 0-millisecond recovery time. Dual-ring communication and dual-data protection improve the reliability of data communication under the ring redundancy topology.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0069] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0070] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus or device (such as a computer-based system, a processor-included system or other system that can fetch and execute instructions from, an instruction execution system, apparatus or device).

[0071] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0072] It should be noted that, in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. An industrial Ethernet ring redundant communication system, characterized in that, Includes a main control station and at least one remote station. The main control station includes a controller, a first switching chip, a first extended communication unit, and at least one first communication or I / O unit. The controller, the first extended communication unit, and the at least one first communication or I / O unit are respectively connected to the first switching chip. The two ports of the first extended communication unit are connected to the first switching chip. At least one remote station includes a second switching chip, a second extended communication unit, and at least one second communication or I / O unit. The second extended communication unit and the at least one second communication or I / O unit are respectively connected to the second switching chip. Two ports of the second extended communication unit are connected to the second switching chip. The first extended communication unit and the second extended communication unit communicate with each other.

2. The system according to claim 1, characterized in that, The controller occupies one communication interface of the first switching chip, the at least one first communication or I / O unit occupies one communication interface of the first switching chip, and the first extended communication unit occupies two communication interfaces of the first switching chip.

3. The system according to claim 1, characterized in that, The at least one second communication or I / O unit occupies one communication interface of the second switching chip, and the second extended communication unit occupies two communication interfaces of the second switching chip.

4. The system according to claim 1, characterized in that, The first extended communication unit and the second extended communication unit communicate with each other via optical fiber or cable.

5. The system according to claim 1, characterized in that, The first extended communication unit and the second extended communication unit include an S1 port, an S2 port, an Up port, and a Down port. The S1 port and S2 port of the first extended communication unit are respectively connected to the two communication interfaces of the first switching chip; The S1 and S2 ports of the second extended communication unit are connected to the two communication interfaces of the second switching chip.

6. The system according to claim 1, characterized in that, The first extended communication unit and the second extended communication unit are designed using FPGA logic, and the MAC layer of the data is packaged internally by the FPGA.

7. The system according to claim 1, characterized in that, The S1 port and Up port of the first extended communication unit and the second extended communication unit are in one group, and the S2 port and Down port are in another group. All ports are connected to the PHY chip.

8. The system according to claim 5, characterized in that, The first extended communication unit and the second extended communication unit include a message judgment subunit. The message judgment subunit determines whether the destination address of a message entering through port S1 or port S2 is this station. If it is not this station, it forwards the message; if it is this station, it discards the message. The message judgment subunit determines whether the source address of a message entering through the Up port or Down port is the local station. If it is not the local station, it is forwarded; if it is the local station, it is discarded.

9. The system according to claim 1, characterized in that, There is at least one controller, and when there are two controllers, the two controllers are mutually redundant, with one being the master and the other the slave.

10. An industrial Ethernet ring redundancy communication method, characterized in that, The method is applied to any one of the industrial Ethernet ring redundancy communication systems described in 1-9, including: When the controller sends a message to the station's I / O, the message is sent directly to the communication or I / O unit through the station's switching chip. The extended communication unit intercepts the message and does not send the message to the remote station. When the controller sends a message to the remote station IO, the message is broadcast through the station's switching chip, and two copies of the message are sent to the remote station IO through the two ports of the extended communication unit. The message is then sent to the target IO unit of the remote station through two communication loops. When the station's internal I / O sends a message to the controller, the message is sent directly to the controller through the station's switching chip. The extended communication unit intercepts the message and does not send the message to the remote station. When the remote station IO sends a message to the controller, the message is broadcast through the remote station's switching chip, and two copies of the message are sent to the controller through the two ports of the remote station's extended communication unit, and then sent to the controller through two communication loops respectively.

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