Large-scale PLC communication method and system based on RapidIO and shared memory technology

Abstract

The invention provides a large-scale PLC communication method and system based on RapidIO and a shared memory technology. The large-scale PLC communication method comprises the steps that S1, a two-layer RapidIO network topology structure and a device module are constructed; the equipment module comprises a proxy communication module; the proxy communication module can undertake a bridging core network and a working area network, and caches all PLC point-to-point shared data in the system through a shared memory component; and S2, enabling the equipment module to use the two layers of RapidIO network topology structures to carry out large-scale PLC communication. According to the invention, the scene of large-scale PLC point-to-point data high-speed communication can be met, a RapidIO core network switch is omitted by adopting the first layer of annular core network structure, and effective data and the like are actively acquired from the shared memory through the PLC equipment in the working area, so that the performance requirement of the switch in the working area is reduced, and the investment cost is reduced for a user.

Description

Technical Field

[0001] The present invention relates to the field of computer technology, and in particular to a large-scale PLC communication method and system based on RapidIO and shared memory technology. Background Art

[0002] Industrial automation PLC controllers, as the most important end nodes for automation, intelligent monitoring and control of modern industrial production lines, carry the connection to the cloud or edge gateway upward, control and monitor local IO modules through the local backplane bus downward, or control and monitor remote IO modules through industrial real-time Ethernet and industrial real-time communication protocols, thereby realizing the interconnection of the cloud, edge and end trinity. Its importance is self-evident. In some medium and large-scale field applications, due to the resource limitations of a single industrial controller itself, or the need for control coordination between multiple workspaces, it is necessary to network multiple PLC controllers and complete high-speed data synchronization. Such requirements often appear in the application site of large-scale industrial production lines, such as hot rolling production lines in steel enterprises, where the number of PLCs in each production section can reach more than 30 in total. In particular, in this system, there is no master-slave relationship between multiple PLCs, but a peer-to-peer network is established. Since the data exchanged between PLCs belongs to the core of the entire control system, it is often necessary to achieve higher communication performance, such as the number of communication connections, delay, jitter, etc. Therefore, we urgently need a solution for a high-speed peer-to-peer communication system to meet the high-speed communication requirements of such large-scale PLC systems.

[0003] For different application scenarios, users hope to be able to select appropriate high-speed communication network technology and data exchange technology based on the needs of site layout, performance indicators, cost investment, etc., and provide system construction solutions. At present, the high-speed communication network and data exchange technologies commonly used by researchers for industrial control systems include: reflective memory solution, RDMA over Ethernet solution, InfiniBand solution, FPGA-based private solution and RapidIO solution, etc.

[0004] However, all of the above methods have certain defects.

[0005] Reflective memory card solution: It can be used for high-speed memory sharing. It was originally developed by VMIC and is now maintained by Abaco Systems. All the reflective memory-based board cores found on the market are provided by this company, which may cause supply chain dependence. Between reflective memory boards, it uses a private communication protocol and only supports ring or star network connections. Between the reflective memory board and the rack, the backplane bus communication can use the VME standard, or the PMC / XMC standard that supports the PCI bus series. In addition, the capital cost of the reflective memory solution is very high. For example, a VME-5565 board costs about eight thousand dollars. The reflective internal solution is limited to rack backplane bus standards such as VME / PMC / XMC, which has limited practical applications.

[0006] RDMA over Ethernet solution: The RDMA protocol can be superimposed on the Ethernet protocol stack to achieve direct access to the remote device memory, that is, the data in the local device memory can be directly accessed to the remote device memory through the DMA controller via the Ethernet connection and memory mapping technology, and no CPU intervention is required. Due to the unreliability of the underlying Ethernet protocol for communication, this solution requires more Ethernet QoS guarantees, such as flow control and congestion control, to ensure overall performance, but common Ethernet cards do not have these functions. Since the RDMA over Ethernet solution requires an Ethernet card with proprietary functions, this will increase the cost of the solution and make it difficult to obtain suppliers.

[0007] InfiniBand solution: It is usually used in applications such as high-speed data centers, and it naturally has RDMA capabilities to directly access remote system memory. Although the standard specifications of InfiniBand are maintained by the public InfiniBand Trade Association, the products on the market are mainly provided by Mellanox. Therefore, the lack of optional suppliers will cause supply chain dependence problems. Since the InfiniBand solution is a communication technology in a specific field, this will increase the cost of the solution and make it difficult to expand the system.

[0008] DMAP memory reflection solution based on FPGA accelerator card: Developed by UEI to replace the existing VMIC reflection memory solution. By optimizing the underlying Ethernet protocol on the FPGA, the DMAP solution can use standard UDP messages to achieve memory reflection between boards. However, since this is a private solution, it may cause supply chain dependence. Due to the lack of multi-specification network switches, network adapter cards, etc., this solution will limit the user's flexible networking application scenarios.

[0009] RapidIO solution: It was initially used for high-speed communication at the chip level, but as the acceptance of applications increases, its use has been expanded to inter-board communication and inter-machine communication. This technology is maintained by the RapidIO Trade Association, and there are many suppliers of technology implementation, including active manufacturers such as IDT, Mercury, Xilinx, and Praesum. There is even open source FPGA code for reference in the open source community OpenCores. The independent use of RapidIO solutions still cannot meet the communication needs of some large-scale PLC control systems. For example, for a hot rolling production line with 32 PLC controllers, a single all-star network-connected RapidIO communication system may encounter the problem of switch forwarding capacity overload when PLC point-to-point data is transmitted concurrently.

[0010] In the Chinese patent document with the publication number CN111078611A, a PLC high-speed backplane bus based on FPGA is disclosed, including a CPU module and a high-speed backplane bus, and the CPU module and the high-speed backplane bus are bidirectionally connected through wires. The FPGA-based PLC high-speed backplane bus is connected to the input end of the PCIExpress interface through the output end of the high-speed backplane bus, and the output end of the PCIExpress interface is connected to the IO module. The CPU module includes a CPU processor, an FPGA chip, a storage module and a system cut-off module. The CPU processor and the FPGA chip are bidirectionally connected, and the CPU processor and the storage module are bidirectionally connected. The PCIExpress interface is used to realize point-to-point and point-to-multipoint data transmission, and the LVDS interface is used for data transmission. The patent document provides high-speed backplane bus communication for the PLC controller through FPGA, which is used to connect I / O modules, but does not involve the networking problem of high-speed peer-to-peer communication of multiple PLCs.

[0011] In a Chinese patent document with publication number CN117707042A, a high-speed PLC expansion bus system is disclosed, which relates to the field of PLC technology. The system includes: a host; at least two functional modules; the functional modules and the functional modules and the host are connected in a cascade manner; an expansion bus, connecting the host and the functional modules, for transmitting power, data and control signals. The patent document expands the bus on the PLC controller through FPGA to connect I / O modules, and implements a loopback or point-to-point connection communication protocol, but does not involve the networking problem of high-speed peer-to-peer communication of multiple PLCs.

[0012] In the Chinese patent document with publication number CN118233409A, a RapidIO communication system based on a soft PLC operating system is disclosed, including a master node and several device nodes. The master node communicates with the device nodes through a RapidIO switch and a RapidIO to PCIX bridge relay. The master node assigns a unique ID to each device node, configures the routing of the device node, and configures the RapidIO address space to translate the RapidIO address space into the CPU address space. The master node uses the DOORBELL communication mechanism to send request events to the device nodes, and receives request events from other device nodes through DOORBELL interrupts. This patent document provides a RapidIO-based data channel for data exchange between devices in a PLC control system, but does not involve the networking problem of high-speed peer-to-peer communication of multiple PLCs.

[0013] In a foreign patent document with publication number US7721001B1, a system and method for time synchronization of operations in a control system are disclosed. A synchronization network and a device are provided for transmitting synchronization information between controllers in a distributed or localized control system, and such synchronization information is used to allow the operation of these controllers to be synchronized with respect to time. A synchronization protocol and hardware device for control operations in a synchronous control system are also disclosed. This patent document solves various synchronization problems in a distributed system, including time synchronization, information synchronization, and data synchronization, and supports synchronous connections between multiple topologies and multiple devices (PLC controllers, I / O devices). To this end, the patent document mainly proposes a corresponding communication protocol to extend the existing synchronization scheme on the same rack to a distributed multi-rack scenario. However, this patent document does not involve the problem of high-speed peer-to-peer exchange of PLC point-to-point data, but rather solves the synchronization problem of the control process of distributed PLC controllers and I / O devices based on time synchronization. Summary of the invention

[0014] In view of the defects in the prior art, the object of the present invention is to provide a large-scale PLC communication method and system based on RapidIO and shared memory technology.

[0015] A large-scale PLC communication method based on RapidIO and shared memory technology provided by the present invention includes:

[0016] Step S1: construct a two-layer RapidIO network topology structure and device modules;

[0017] The two-layer RapidIO network topology includes a ring-star network, and the first layer core network uses a RapidIO ring network to connect various workspaces;

[0018] The device module includes a PLC controller, a RapidIO communication module and an agent communication module;

[0019] The PLC controller is integrated with or connected to a RapidIO communication module via a bus;

[0020] The proxy communication module can bridge the core network and the work area network, and cache all PLC point-to-point shared data in the system through a shared memory component, thereby reducing the system's performance requirements for the work area switch;

[0021] Step S2: The device modules use a two-layer RapidIO network topology to perform large-scale PLC communication.

[0022] Preferably, the method supports the concept of logical workspaces, assuming that all controls at the user site are in one workspace, and groups all PLCs into different logical workspaces to build a topological structure of the system network; in the two-layer RapidIO network topology, there is no core switch in the first-layer ring core network.

[0023] Preferably, the RapidIO ring network sequentially transfers global shared memory data to each workspace.

[0024] Preferably, each PLC device in the workspace actively obtains the required point-to-point shared data of other PLCs from the shared memory component of the proxy communication module; if there is transmission collaboration within the workspace, each PLC device can plan its own access time to the shared memory on the proxy communication module.

[0025] Preferably, the first layer core network is networked by a main agent communication module, and the work area switch belongs to an independent module or an agent communication module.

[0026] A large-scale PLC communication system based on RapidIO and shared memory technology provided by the present invention includes:

[0027] Two-layer RapidIO network topology and device modules;

[0028] The two-layer RapidIO network topology includes a ring-star network, and the first layer core network uses a RapidIO ring network to connect various workspaces;

[0029] The device module includes a PLC controller, a RapidIO communication module and an agent communication module;

[0030] The PLC controller is integrated with or connected to a RapidIO communication module via a bus;

[0031] The proxy communication module can bridge the core network and the work area network, and cache all PLC point-to-point shared data in the system through a shared memory component, thereby reducing the system's performance requirements for the work area switch;

[0032] The device modules use a two-layer RapidIO network topology for large-scale PLC communication.

[0033] Preferably, the system supports the concept of logical workspaces, assuming that all controls at the user site are in one workspace, and grouping all PLCs into different logical workspaces to construct the topology of the system network; in the two-layer RapidIO network topology, there is no core switch in the first-layer ring core network.

[0034] Preferably, the RapidIO ring network sequentially transfers global shared memory data to each workspace.

[0035] Preferably, each PLC device in the workspace actively obtains the required point-to-point shared data of other PLCs from the shared memory component of the proxy communication module; if there is transmission collaboration within the workspace, each PLC device can plan its own access time to the shared memory on the proxy communication module.

[0036] Preferably, the first layer core network is networked by a main agent communication module, and the work area switch belongs to an independent module or an agent communication module.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The method proposed in the present invention adopts a two-layer RapidIO network topology structure and various device modules, which can meet the scenario of large-scale PLC point-to-point data high-speed communication; in terms of cost, the present invention adopts the first-layer ring core network structure to eliminate the RapidIO core network switch, and actively obtains valid data from the shared memory through the internal PLC device of the work area, thereby reducing the performance requirements of the work area switch and reducing the investment cost for users.

[0039] 2. The layered network structure and modular system architecture adopted by the present invention provide users with a flexible expansion and cost-effective solution with high practicality.

[0040] Other beneficial effects of the present invention will be explained in the specific implementation manner through the introduction of specific technical features and technical solutions. Through the introduction of these technical features and technical solutions, those skilled in the art should be able to understand the beneficial technical effects brought about by the technical features and technical solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0042] Figure 1 The figure is a flow chart of the method of the present invention.

[0043] Figure 2 It is a schematic diagram of the industrial control site layout of the present invention.

[0044] Figure 3 This is a two-layer ring-star topology diagram in the present invention.

[0045] Figure 4 It is the structural diagram of the PLC controller in the present invention.

[0046] Figure 5 This is a structural diagram of the proxy communication module in the present invention. DETAILED DESCRIPTION

[0047] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0048] Reference Figure 1 As shown, a large-scale PLC communication method based on RapidIO and shared memory technology includes:

[0049] Step S1: construct a two-layer RapidIO network topology structure and various device modules. The two-layer RapidIO network topology structure includes a ring-star network; the device modules include a PLC controller, an agent communication module, a RapidIO communication module, and a workspace switch.

[0050] The present invention supports the concept of logical workspaces, assuming that all controls at the user site are in one workspace, and groups all PLCs into different logical workspaces to construct the topology of the system network. In the two-layer RapidIO network topology, the core switch is omitted in the first-layer ring core network.

[0051] The first core network of the two-layer ring-star network uses a RapidIO ring network to connect each workspace to eliminate the core network switch. The ring network transmits global shared memory data to each workspace in turn.

[0052] The proxy communication module can bridge the core network and the work area network, and cache all PLC point-to-point shared data in the system through shared memory components, reducing the system's performance requirements for the work area switch. The proxy communication module has two SRIO ports for the core network to access the core ring network. The data transmission and storage between the proxy communication modules are completed by the SRIO DMA channel and memory mapping. After completing a transmission, the sender will inform the receiver through the SRIO DOORBELL message, so as to process each node of the ring network in turn.

[0053] Regarding bridging, through the above-mentioned SRIO-based DMA channel and memory mapping data transmission process, shared data is stored in the user access area. Therefore, the PLCs inside the workspace can use the message mechanism or the shared memory mechanism (which requires similar SRIO memory mapping capabilities or RDMA over Ethernet) to obtain the required data.

[0054] The PLC controller includes a communication module that is integrated or connected to RapidIO through a bus; within the workspace, each PLC device actively obtains the required point-to-point shared data of other PLCs from the shared memory component of the proxy communication module; if there is transmission collaboration within the workspace, each PLC device can plan its own access time to the shared memory on the proxy communication module.

[0055] Step S2: large-scale PLC communication is realized based on the constructed two-layer RapidIO network topology and device modules.

[0056] The present invention can meet the scenario of large-scale PLC point-to-point data high-speed communication by adopting a two-layer RapidIO network topology and various device modules; in terms of cost, the present invention eliminates the RapidIO core network switch by adopting the first-layer ring core network structure, and actively obtains valid data from the shared memory through the internal PLC device of the work area, thereby reducing the performance requirements of the work area switch and reducing the investment cost for users. At the same time, the layered network structure and modular system architecture provide users with a flexible expansion and cost-effective solution.

[0057] The above is a basic embodiment of the present invention. The technical solution of the present invention is further described below through a preferred embodiment.

[0058] Example 1

[0059] For high-speed peer-to-peer communication in large PLC control systems, the present invention supports users to select the topology of the control network and the required device modules according to the industrial control site layout and performance requirements, such as PLC controllers (integrated or connected to RapidIO communication modules through buses) and proxy communication modules. Figure 2 As shown, there are 4 work areas on site, each with 6 PLC controllers. During operation, each PLC may exchange data with other PLCs in a point-to-point manner.

[0060] In this embodiment, the corresponding PLCs are referred to as data producers and data consumers, and this communication relationship is called a peer-to-peer network. Within a control cycle, all producer data must be updated to the consumer end in a timely manner. For example, for a PLC control system with a control cycle of "1ms", according to the sampling theorem, the PLC data exchange cycle needs to be 1 / 2 of the control cycle, that is, "500us". Generally, this control system with a communication cycle of less than 5ms and supporting a large number of PLC point-to-point data communications is called a large-scale PLC high-speed communication system. Not limited to the above examples, the present invention supports user sites with layouts that are different from Figure 2 In addition, it supports the concept of logical workspaces, that is, assuming that all controls on the user's site are in one workspace, all PLCs can still be grouped into different logical workspaces to build the topology of the system network. In the present invention, the system network topology can be: Figure 3 As shown, a two-layer ring-star network. The device modules can be: PLC controller, RapidIO communication module, agent communication module, work area switch.

[0061] exist Figure 3 In the two-layer ring-star network, the first-layer core network uses a RapidIO ring network to connect four workspaces, thus eliminating the need for a core network switch. This ring network will sequentially transmit global shared memory data to each workspace. Assuming that there are a total of 28 devices in the four workspaces in the system, each with "20kB / ms" of shared data, the bandwidth of the global shared memory data that needs to be transmitted is "20kB / ms×28=560kB / ms=4.48Gpbs". Considering the 8 / 10 encoding rate of SerialRapidIO technology, the required network bandwidth is "4.48Gpbs×1.25=5.6Gbps". Therefore, the proxy communication module needs to support the RapidIO Gen2.1 communication interface, that is, each x1 channel has a 5Gbps transmission rate, and the maximum supported bus bandwidth of four channels is 20Gbps.

[0062] In contrast, in the case of a full star network, not only does it need to add a core network switch, but the switch may be overloaded in the scenario of PLC point-to-point data communication. Taking the above assumption as an example, a switch port connected to a terminal device may forward the point-to-point shared data of all other terminal devices in the system at the same time, so the maximum forwarding data bandwidth of this port may be "20kB / ms×27=540kB / ms=4.32Gpbs". Because there are a total of 28 devices connected to the switch, the switching capacity of the switch must be greater than "4.32Gbps×28=120Gbps", which is converted to Serial RapidIO rate "120Gpbs×1.25=150Gbps". For Renesas' CPS-1616 switch chip, the maximum switching capacity is only "80Gbps". What is more difficult is that even the most advanced RXS2448 switch chip of Renesas (RapidIO Gen3.2 standard) has only 24 switch ports, so a full star network structure that requires multiple switches to be cascaded will appear, which will cause more usage obstacles including management and diagnosis. In fact, the reason why such a large switching capacity is needed is entirely because the entire system lacks data transmission coordination, which will cause data concurrency; and the data sharer will broadcast its shared data to all other terminal devices, so in this seemingly huge data exchange, a large part of the data is invalid for some receivers.

[0063] Within the workspace, each PLC device will actively obtain the required point-to-point shared data of other PLCs from the shared memory component of the proxy communication module:

[0064] First, when using engineering software to configure the system, it is necessary to establish a connection between each PLC and the corresponding shared memory area on the proxy communication module for the shared data that needs to be obtained. This can be based on a message mechanism or shared memory technology.

[0065] Secondly, if the internal network of the workspace can achieve time synchronization, such as time-synchronous Ethernet based on IEEE1588, then the execution time of the PLC task can be further planned in the engineering software, thereby achieving orderly access to the shared memory on the proxy communication module according to time slice planning.

[0066] Finally, at runtime, since each PLC only accesses the data it needs, and time-planned, orderly access is possible, the network burden, risk, and cost within the workspace are reduced.

[0067] The specific content of these exchanged data is determined by the needs of each PLC. Since the amount of data is usually small in actual applications, it can avoid the situation where each PLC device passively accepts a large amount of invalid data mentioned in the full star network above. If there is transmission coordination within the workspace, each PLC device can even plan its own access time to the shared memory on the proxy communication module, thereby avoiding data flow collisions and high bandwidth requirements for switches:

[0068] Planning based on time slices requires the ability to achieve time synchronization between nodes. In the current plan, the Ethernet-based IEEE1588 protocol is very mature and can be used directly.

[0069] Time synchronization based on SRIO requires protocol specifications above version v3.1. Based on time synchronization, the engineering software can schedule tasks for PLC according to time instead of in free running mode.

[0070] In general, the present invention proposes a two-layer network structure based on RapidIO. In the first-layer ring core network, the core switch is omitted; and the proxy communication module inside the work area, in addition to assuming the function of bridging the core network and the work area network, can also cache all PLC point-to-point shared data in the system through a shared memory component, thereby reducing the system's performance requirements for the work area switch. Therefore, large-scale PLC high-speed communication can be achieved while saving investment expenses.

[0071] Corresponding to the above solution, the devices supported by the present invention include but are not limited to PLC controllers, RapidIO communication modules, proxy communication modules, and workspace switches. Figure 4 As shown, the PLC controller has a RapidIO communication module to access the RapidIO star network inside the workspace. Optionally, the PLC controller can also have a shared memory to achieve high-speed peer-to-peer data exchange between PLCs. Figure 5 As shown, the proxy communication module has multiple RapidIO communication modules for accessing the RapidIO ring core network, and can also have a RapidIO switch for realizing data exchange of PLC devices inside the workspace. The proxy communication module also has a shared memory component for caching all PLC point-to-point shared data in the system, and coordinating the transmission of shared data on the first-layer core network and the second-layer workspace network. In addition, the first-layer ring core network is networked by a master proxy communication module. The workspace switch can be an independent module or a part of the proxy communication module, supporting the RapidIO protocol, but does not exclude the use of the Ethernet protocol in the case of low data bandwidth requirements.

[0072] The present invention also provides a large-scale PLC communication system based on RapidIO and shared memory technology. The large-scale PLC communication system based on RapidIO and shared memory technology can be implemented by executing the process steps of the large-scale PLC communication method based on RapidIO and shared memory technology, that is, those skilled in the art can understand the large-scale PLC communication method based on RapidIO and shared memory technology as a preferred implementation of the large-scale PLC communication system based on RapidIO and shared memory technology.

[0073] Specifically, a large-scale PLC communication system based on RapidIO and shared memory technology includes:

[0074] Two-layer RapidIO network topology and device modules;

[0075] The two-layer RapidIO network topology includes a ring-star network, and the first layer core network uses a RapidIO ring network to connect various workspaces;

[0076] The device module includes a PLC controller, a RapidIO communication module and an agent communication module;

[0077] The PLC controller is integrated with or connected to a RapidIO communication module via a bus;

[0078] The proxy communication module can bridge the core network and the work area network, and cache all PLC point-to-point shared data in the system through a shared memory component, thereby reducing the system's performance requirements for the work area switch;

[0079] The device modules use a two-layer RapidIO network topology for large-scale PLC communication.

[0080] The system supports the concept of logical workspaces, assuming that all controls at the user site are in one workspace, and groups all PLCs into different logical workspaces to build the topology of the system network; in the two-layer RapidIO network topology, there is no core switch in the first-layer ring core network.

[0081] The RapidIO ring network sequentially transfers the global shared memory data to each workspace.

[0082] Each PLC device in the workspace actively obtains the required point-to-point shared data of other PLCs from the shared memory component of the proxy communication module; if there is transmission collaboration within the workspace, each PLC device can plan its own access time to the shared memory on the proxy communication module.

[0083] The first layer core network is networked by a main agent communication module, and the work area switch belongs to an independent module or an agent communication module.

[0084] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0085] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0086] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A large-scale PLC communication method based on RapidIO and shared memory technology, characterized in that: include: Step S1: construct a two-layer RapidIO network topology structure and device modules; The two-layer RapidIO network topology includes a ring-star network, and the first layer core network uses a RapidIO ring network to connect various workspaces; The device module includes a PLC controller, a RapidIO communication module and an agent communication module; The PLC controller is integrated with or connected to a RapidIO communication module via a bus; The proxy communication module can bridge the core network and the work area network, and cache all PLC point-to-point shared data in the system through a shared memory component, thereby reducing the system's performance requirements for the work area switch; Step S2: The device modules use a two-layer RapidIO network topology to perform large-scale PLC communication.

2. The large-scale PLC communication method based on RapidIO and shared memory technology according to claim 1, characterized in that: The method supports the concept of logical workspaces, assuming that all controls at the user site are in one workspace, and groups all PLCs into different logical workspaces to construct a topological structure of the system network; in the two-layer RapidIO network topology, there is no core switch in the first-layer ring core network.

3. The large-scale PLC communication method based on RapidIO and shared memory technology according to claim 2, characterized in that: The RapidIO ring network sequentially transfers the global shared memory data to each workspace.

4. The large-scale PLC communication method based on RapidIO and shared memory technology according to claim 2, characterized in that: Each PLC device in the workspace actively obtains the required point-to-point shared data of other PLCs from the shared memory component of the proxy communication module; if there is transmission collaboration within the workspace, each PLC device can plan its own access time to the shared memory on the proxy communication module.

5. The large-scale PLC communication method based on RapidIO and shared memory technology according to claim 1, characterized in that: The first layer core network is networked by a main agent communication module, and the work area switch belongs to an independent module or an agent communication module.

6. A large-scale PLC communication system based on RapidIO and shared memory technology, characterized in that: include: Two-layer RapidIO network topology and device modules; The two-layer RapidIO network topology includes a ring-star network, and the first layer core network uses a RapidIO ring network to connect various workspaces; The device module includes a PLC controller, a RapidIO communication module and an agent communication module; The PLC controller is integrated with or connected to a RapidIO communication module via a bus; The proxy communication module can bridge the core network and the work area network, and cache all PLC point-to-point shared data in the system through a shared memory component, thereby reducing the system's performance requirements for the work area switch; The device modules use a two-layer RapidIO network topology for large-scale PLC communication.

7. The large-scale PLC communication system based on RapidIO and shared memory technology according to claim 6, characterized in that: The system supports the concept of logical workspaces, assuming that all controls at the user site are in one workspace, and groups all PLCs into different logical workspaces to build the topology of the system network; in the two-layer RapidIO network topology, there is no core switch in the first-layer ring core network.

8. The large-scale PLC communication system based on RapidIO and shared memory technology according to claim 7, characterized in that: The RapidIO ring network sequentially transfers the global shared memory data to each workspace.

9. The large-scale PLC communication system based on RapidIO and shared memory technology according to claim 7, characterized in that: Each PLC device in the workspace actively obtains the required point-to-point shared data of other PLCs from the shared memory component of the proxy communication module; if there is transmission collaboration within the workspace, each PLC device can plan its own access time to the shared memory on the proxy communication module.

10. The large-scale PLC communication system based on RapidIO and shared memory technology according to claim 6, characterized in that: The first layer core network is networked by a main agent communication module, and the work area switch belongs to an independent module or an agent communication module.

Images