A method for accessing and configuring industrial control equipment in a publish-subscribe mode that distinguishes determinism

Abstract

The present invention discloses a method for accessing and configuring industrial control equipment in a publish-subscribe mode that distinguishes determinism. The method includes: a discovery server obtains initial device information for static devices; an IDE requests and obtains registered static devices and their initial device information from the discovery server; device configuration information for programmable devices and static devices is constructed; the discovery server integrates all device configuration information and sends it to a network manager; the network manager formulates communication policies for publish-subscribe devices and switches; the discovery server sends the communication policy configuration information to all devices; and all devices perform device connection, topic association, and publish-subscribe communication according to the communication policy configuration information. The method of the present invention enables an industrial control system to support flexible access and automatic configuration of devices in the publish-subscribe mode, improving the determinism of real-time information transmission and the carrying capacity of non-real-time information transmission in the publish-subscribe mode.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial control systems, and more particularly to a device access and configuration method for a publish-subscribe mode with differentiated determinism for industrial control systems. Background Art

[0002] With the rapid development of the Industrial Internet, the demand for the integration of IT and OT systems is growing stronger. The scope of industrial control systems has further expanded, from traditional, local OT-side industrial control systems consisting of PLCs and I / O to wider areas encompassing edge computing platforms, even cloud platforms, and IT systems. Information exchange between system devices is becoming increasingly extensive. The localized, fixed model of traditional industrial systems, limited by resources and scope, is no longer able to support application requirements. Opening up previously isolated data and information within industrial control systems and supporting flexible access and data acquisition from external devices has become the development direction of industrial control systems in this new era.

[0003] The publish-subscribe model (Pub / Sub) is an asynchronous messaging model in the IT field, offering more flexible data transmission. Publishers publish messages to specific topics without worrying about who receives them. Subscribers only care about topics of interest and receive messages only for those topics they subscribe to. The publish-subscribe model allows for the dynamic addition and removal of subscribers, and the publisher and subscriber relationships associated with a topic can change at any time.

[0004] Applying Pub / Sub communication to industrial control systems can address the issue of system communication flexibility. However, since traditional industrial control systems rely on fixed connections based on device binding, Pub / Sub communication is not suitable. Therefore, on the one hand, it is necessary to change the device access method of industrial control systems to support Topic-based Pub / Sub communication, enabling flexible device access and data exchange. On the other hand, industrial control systems have high requirements for the real-time and reliability of industrial application data communication. However, conventional Pub / Sub communication methods are mainly designed for non-real-time data transmission and cannot guarantee the deterministic data requirements of industrial control systems.

[0005] Through the method of the present invention, the industrial control system can support flexible access and automatic configuration of devices in the publish-subscribe mode, and improve the certainty of real-time information transmission and the carrying performance of non-real-time information transmission of the industrial control system in the publish-subscribe mode. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a device access and configuration method for a publish-subscribe mode with differentiated determinism for an industrial control system.

[0007] The present invention adopts the following technical solution: a method for accessing and configuring industrial control equipment in a publish-subscribe mode that distinguishes determinism, comprising the following steps:

[0008] The static device sends a device registration request to the discovery server. The discovery server authenticates the static device and allows the device to access if it meets the authentication criteria, completing the device registration. The discovery server sends a device configuration read request to the registered static device to obtain the initial device information of the static device.

[0009] The IDE requests and obtains the registered static device and its initial device information from the discovery server; based on the obtained registered static device and initial device information, the IDE configures the publish-subscribe communication relationship and communication QoS requirements between the programmable device and the static device, obtains the device configuration information of the programmable device and the static device, and sends it to the discovery server;

[0010] The discovery server consolidates all device configuration information and sends it to the network manager;

[0011] The network manager formulates communication strategies for the publishing and subscribing devices and switches based on the device locations, network communication link resources, and device configuration information of the publishing and subscribing communication relationships. The network manager also configures the switches according to the communication strategies and returns the formulated communication strategy configuration information to the discovery server.

[0012] The discovery server sends the communication policy configuration information to all devices: for static devices, the communication policy configuration information is directly sent; for programmable devices, the communication policy configuration information is sent to the IDE, which compiles it into the program configuration and sends it to the programmable device;

[0013] All devices perform device connection, topic association and publish-subscribe communication according to the communication strategy configuration information.

[0014] The initial device information of the static device includes the device role pub or sub, the reader Reader, the writer Writer, and the topic Topic.

[0015] The initial device information includes:

[0016] Device role information: publisher (publisher or pub), subscriber (subscriber or sub), message broker (broker);

[0017] Reader information: including reader name and related subject information;

[0018] Writer information: including writer name and related topic information;

[0019] Topic information: including Topic name, Topic data type, and Topic length.

[0020] The device configuration information includes:

[0021] Device role information: publisher (i.e., Publisher or Pub), subscriber (i.e., Subscriber or Sub), message broker (Broker);

[0022] Reader information: including reader name, related topic information, and subscription period;

[0023] Writer information: including writer name, related topic information, and publishing cycle;

[0024] Topic information: including Topic name, Topic data type, Topic length, and QoS requirements;

[0025] Among them, QoS requirements include: real-time type and reliable type.

[0026] The device communication strategy configuration information includes:

[0027] Reader QoS information: including subscription period, priority or time slot, reliability configuration, and persistence configuration;

[0028] Writer QoS information: including release cycle, priority / time slot, reliability configuration, and persistence configuration;

[0029] Topic information: including Topic name, Broker address or Topic multicast group address.

[0030] The network manager formulates communication strategies for publish-subscribe devices and switches based on device locations, network communication link resource conditions, and device configuration information of publish-subscribe relationships, including:

[0031] Real-time topics are distributed using multicast. The Writer sets the destination address of the real-time topic to the configured topic multicast group address, which is then forwarded by the network switch or router to the readers in the multicast group.

[0032] For non-real-time topics, the Broker message agent forwarding method is adopted; the Writer sends the non-real-time topic to the configured Broker, and the Reader obtains the subscribed topic from the Broker; and according to the device location and network load, different Brokers are selected to load balance the traffic.

[0033] A deterministic publish-subscribe industrial control equipment access and configuration system, comprising:

[0034] Static devices are used to send device registration requests and initial device information to the discovery server, and receive and execute the communication policy configuration of the discovery server;

[0035] Programmable device for executing user-developed logic control and discovery server communication strategy configuration based on the program and configuration downloaded from the IDE;

[0036] The discovery server is used to interact with static devices, authenticate static devices, and allow access to static devices that meet the authentication conditions, completing device registration. The discovery server sends a device configuration read request to the registered static device to obtain the initial device information of the static device. The discovery server is used to interact with the IDE, respond to the IDE's request to register static devices and obtain their initial device information, and obtain the device configuration information of programmable devices and static devices configured by the IDE. The discovery server is used to interact with the network manager, send all integrated device configuration information to the network manager, and send the communication policy configuration information sent by the network manager to all devices.

[0037] The IDE is used to request the discovery server to register static devices and initial device information, and obtain the registered static devices and their initial device information; based on the obtained registered static devices and initial device information, configure the publish-subscribe communication relationship and communication QoS requirements between the programmable device and the static device, obtain the device configuration information of the programmable device and the static device, and send it to the discovery server;

[0038] The network manager is used to formulate communication strategies for publishing and subscribing devices and switches based on device locations, network communication link resources, and device configuration information of the publish-subscribe relationship; configure switches according to the communication strategies, and return the formulated communication strategy configuration information to the discovery server;

[0039] All devices including static devices, programmable devices and their IDEs, discovery servers, and network managers are used to perform device connection, topic association, and publish-subscribe communication according to the communication strategy configuration information.

[0040] The present invention has the following beneficial effects and advantages:

[0041] 1. It can enable industrial control systems to support flexible access and automatic configuration of devices in the publish-subscribe mode

[0042] 2. Improve the determinism of real-time information transmission and the carrying performance of non-real-time information transmission in the publish-subscribe mode of industrial control systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram of an embodiment of a system for accessing and configuring industrial control equipment in a publish-subscribe mode with deterministic differentiation according to the present invention;

[0044] Figure 2 A flowchart of an embodiment of a method for accessing and configuring industrial control equipment in a publish-subscribe mode with deterministic differentiation according to the present invention;

[0045] Figure 3 A schematic diagram of an embodiment of the present invention for distinguishing configuration information of a deterministic publish-subscribe model;

[0046] FIG4(a) is a schematic diagram of an embodiment of the present invention for distinguishing deterministic publish-subscribe mode communication strategy Figure 1 ;

[0047] FIG4( b ) is a schematic diagram of an embodiment of the present invention for distinguishing deterministic publish-subscribe mode communication strategy Figure 2 . DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] See also Figure 1 , a schematic diagram of an embodiment of a data distribution system for industrial control systems based on a deterministic publish-subscribe model according to the present invention;

[0050] The data distribution system includes industrial equipment and data distribution equipment.

[0051] Industrial equipment includes PLCs, I / O devices, edge devices, and computers. Industrial devices are connected and communicate data via a network. The PLC, as the master control unit of an industrial control system, is responsible for the operational processing logic of the devices within its control range. Before the PLC can be officially put into operation, system configuration (configuration) and application programming and compilation are required using a computer's integrated development environment (IDE). The configured and compiled executable file is then downloaded to the PLC for execution. Devices can be divided into two categories based on their intelligence level—i.e., whether they support programmability. Static devices, for example, have fixed device functions at the factory and cannot be modified programmatically. For example, for I / O devices, the device information configuration (called initial device information) is pre-set at the factory. Programmable devices, such as PLCs and edge controllers, support programmable modifications using the accompanying development environment (IDE), and device information configuration can be customized according to the developer's needs.

[0052] Data distribution devices include discovery servers, brokers, network switches, and network managers. Data distribution devices are responsible for data forwarding and transmission. The discovery server is responsible for device discovery, registration, configuration, and management of device publish and subscription information. It interacts with the network manager to enable collaborative configuration management of network and terminal devices. Brokers are proxy devices that aggregate and distribute topic messages. Topic messages from publishers are sent to the broker, as are subscription requests from subscribers. The broker then matches published and subscribed topics and forwards any successfully matched topics to the subscriber.

[0053] See also Figure 2 The present invention provides a flow chart of an embodiment of a method for accessing and configuring devices in a publish-subscribe mode with deterministic differentiation for an industrial control system, including:

[0054] Step 201: The static device starts to go online and sends a device registration request to the discovery server. The discovery server authenticates the static device. If the device meets the authentication conditions, the device is allowed to access and the device registration is completed.

[0055] Step 202: The discovery server sends a device configuration read request to the registered static device to obtain the initial device information of the static device;

[0056] Step 203: When the IDE starts device scanning, it requests the registered device and initial device information from the discovery server. The discovery server sends the registered device and initial device information to the IDE.

[0057] Step 204: Based on the acquired registered device and initial device information and the communication relationship of the control application, the IDE configures the communication relationship and communication QoS requirements between the programmable device and the static device, and obtains the device configuration information of the programmable device and the static device. The IDE sends the device configuration information to the discovery server.

[0058] Step 205: The discovery server integrates all device configuration information and sends it to the network manager.

[0059] Step 206: The network manager formulates a communication strategy for the publishing and subscribing devices and switches based on the device locations, network communication link resources, and the device configuration information of the publish-subscribe relationship. The network manager configures the switches according to the communication strategy and returns the formulated device communication strategy configuration information to the discovery server.

[0060] Real-time topics are distributed using multicast. The Writer sets the destination address of the real-time topic to the configured topic multicast group address, which is then forwarded by the network switch / router to the readers in the multicast group.

[0061] Non-real-time topics are forwarded using a broker message agent. Writers send non-real-time topics to the configured broker, and readers obtain subscribed topics from the broker. Different brokers are selected for traffic load balancing based on device location and network load.

[0062] Step 207: The discovery server sends the communication policy configuration information to each device. The communication policy configuration information of the static device is directly sent, and the programmable device needs to send the configuration information to the IDE, which is then compiled into the program configuration and sent to the programmable device.

[0063] Step 208: After the control system is officially started, the device performs device connection, topic association and publish-subscribe communication according to the communication strategy configuration.

[0064] See also Figure 3 , a schematic diagram of an embodiment of the present invention for distinguishing deterministic publish-subscribe mode configuration information, including:

[0065] Initial device information is inherent to static devices and is generally related to the functions supported by the device itself. For example, a digital input device in an I / O device has a device role of publisher, contains at least one writer, and its associated topic is the device's data input value. A digital output device has a device role of subscriber, contains at least one reader, and its associated topic is the device's data output value.

[0066] The initial device information includes:

[0067] Device role information: divided into publisher (Publisher / Pub), subscriber (Subscriber / Sub), and message broker (Broker).

[0068] Reader information: includes the reader name and related subject information.

[0069] Writer information: includes the writer name and related topic information.

[0070] Topic information: includes Topic name, Topic data type, and Topic length.

[0071] Device configuration information is the information about each device formed after the IDE configures the publish-subscribe relationship and QoS requirements. Based on the application logic's requirements for data communication, users configure the publish-subscribe relationship between topics between devices through the IDE, and declare the required publish-subscribe cycle, subject real-time performance, and reliability QoS requirements to form the overall device configuration information for the industrial control system's publish-subscribe function. Device configuration information specifically includes:

[0072] Device role information: divided into publisher (Publisher / Pub), subscriber (Subscriber / Sub), and message broker (Broker)

[0073] Reader information: includes reader name, associated topic information, and subscription period.

[0074] Writer information: includes the writer name, associated topic information, and publishing cycle.

[0075] Topic information: includes topic name, topic data type, topic length, and QoS requirements. QoS requirements include real-time type (differentiated into real-time and non-real-time) and reliability type (differentiated into reliable and unreliable).

[0076] The device communication strategy configuration information is the configuration information of the device communication strategy formed by the network manager after the algorithm calculates and generates the communication strategy based on the device configuration information of the publish-subscribe relationship, network resource usage, device location and other information. It includes the periodic parameters of the publishing and subscribing ends (Reader and Writer), the priority / time slot set to adapt to the real-time transmission of the Topic, the transmission configuration required for reliability assurance, the setting of the Topic data retention time, etc. It also includes the configuration parameters corresponding to the Topic forwarding strategy (Broker address / Topic multicast group address). For real-time Topics, multicast is used for distribution, corresponding to the Topic multicast group address parameters; for non-real-time Topics, Broker message agent forwarding is used, corresponding to the Broker address parameters. The device communication strategy configuration information specifically includes:

[0077] Reader QoS information: including subscription period, priority / time slot, reliability configuration, and persistence configuration (differentiated as retaining the latest data, retaining all historical data, and deleting historical data after a certain period of time)

[0078] Writer QoS information: including release cycle, priority / time slot, reliability configuration, and persistence configuration (differentiated as retaining the latest data, retaining all historical data, and deleting historical data after a certain period of time)

[0079] Topic information: including Topic name, Broker address / Topic multicast group address

[0080] The device communication policy configuration information will be sent to each corresponding device, and the device will execute according to the configuration.

[0081] 4(a) and 4(b) are schematic diagrams of an embodiment of a publish-subscribe communication strategy for distinguishing determinism according to the present invention, including:

[0082] The IO device acts as a publisher and contains two writers. Writer 1 publishes Topic 1, and Writer 2 publishes Topic 2. The edge device acts as a subscriber and contains three readers. Reader 1 subscribes to Topic 2, Reader 2 subscribes to Topic 3, and Reader 3 subscribes to Topic 4. The PLC has two roles: a publisher and two writers. Writer 1 publishes Topic 3, and Writer 2 publishes Topic 4. As a subscriber, it contains two readers. Reader 1 subscribes to Topic 1, and Reader 2 subscribes to Topic 2. The system includes two brokers. Broker 1 forwards Topic 3, and Broker 2 forwards Topic 4. Topic 1 and Topic 2 are real-time topics, while Topic 3 and Topic 4 are non-real-time topics.

[0083] Figure 4(a) illustrates the publish-subscribe communication strategy for real-time Topic 2. Through the communication strategy established by the network manager, real-time Topic 2 uses multicast for data distribution, which improves the real-time nature of data transmission. Readers subscribed to Topic 2 are assigned to a multicast group. When Topic 2 is published to the network, the Writer sets the destination address of Topic 2 to the configured multicast address. The network switch replicates Topic 2's data packets based on the multicast address and forwards them directly to the devices in the group (PLCs and edge devices).

[0084] Figure 4(b) shows the publish-subscribe communication strategy for non-real-time Topic 3 and Topic 4. Non-real-time Topics use the Broker message agent forwarding method. Since all Topics need to be forwarded through the Broker, the Broker's network pressure is relatively high. Therefore, the present invention selects the Broker assigned to the Topic for load balancing, reduces the Broker's network pressure, and improves the carrying capacity of the entire system. Through the communication strategy formulated by the network manager, different Brokers are selected to load balance the traffic according to the device location and network load. Non-real-time Topic 3 uses Broker 1 message agent forwarding, and Topic 4 uses Broker 2 message agent forwarding. Writer 1 of the PLC device sends Topic 3 to the configured Broker 1 according to the communication strategy formulated by the network manager. Reader 2 of the edge device subscribes to Topic 3 from Broker 1 according to the communication strategy. When Topic 3 is published to the network, the Topic 3 data packet will first be sent to Broker 1, which will temporarily store and manage it. When the subscription request is matched, the Topic 3 data will be sent to Reader 2 of the edge device. Similarly, the processing process of Topic4 is similar to Topic3, except that Broker2 is selected for forwarding.

[0085] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0086] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for accessing and configuring industrial control equipment in a publish-subscribe mode that distinguishes determinism, characterized in that: The following steps are involved: The static device sends a device registration request to the discovery server. The discovery server authenticates the static device and allows the device to access if it meets the authentication criteria, completing the device registration. The discovery server sends a device configuration read request to the registered static device to obtain the initial device information of the static device. The IDE requests and obtains the registered static device and its initial device information from the discovery server; based on the obtained registered static device and initial device information, the IDE configures the publish-subscribe communication relationship and communication QoS requirements between the programmable device and the static device, obtains the device configuration information of the programmable device and the static device, and sends it to the discovery server; The discovery server consolidates all device configuration information and sends it to the network manager; The network manager formulates communication strategies for publishing and subscribing devices and switches based on device locations, network communication link resource conditions, and device configuration information of publish-subscribe communication relationships; And configure the switch according to the communication strategy, and return the communication strategy configuration information to the discovery server; The discovery server sends the communication policy configuration information to all devices: for static devices, the communication policy configuration information is directly sent; for programmable devices, the communication policy configuration information is sent to the IDE, which compiles it into the program configuration and sends it to the programmable device; All devices perform device connection, topic association and publish-subscribe communication according to the communication strategy configuration information.

2. The method for accessing and configuring industrial control equipment in a publish-subscribe mode with deterministic differentiation according to claim 1, characterized in that: The initial device information of the static device includes the device role pub or sub, the reader Reader, the writer Writer, and the topic Topic.

3. The method for accessing and configuring industrial control equipment in a publish-subscribe mode with deterministic differentiation according to claim 1, characterized in that: The initial device information includes: Device role information: publisher (publisher or pub), subscriber (subscriber or sub), message broker (broker); Reader information: including reader name and related subject information; Writer information: including writer name and related topic information; Topic information: including Topic name, Topic data type, and Topic length.

4. The method for accessing and configuring industrial control equipment in a publish-subscribe mode with deterministic differentiation according to claim 1, characterized in that: The device configuration information includes: Device role information: publisher (i.e., Publisher or Pub), subscriber (i.e., Subscriber or Sub), message broker (Broker); Reader information: including reader name, related topic information, and subscription period; Writer information: including writer name, related topic information, and publishing cycle; Topic information: including Topic name, Topic data type, Topic length, and QoS requirements; Among them, QoS requirements include: real-time type and reliable type.

5. The method for accessing and configuring industrial control equipment in a publish-subscribe mode with deterministic differentiation according to claim 1, characterized in that: The device communication strategy configuration information includes: Reader QoS information: including subscription period, priority or time slot, reliability configuration, and persistence configuration; Writer QoS information: including release cycle, priority / time slot, reliability configuration, and persistence configuration; Topic information: including Topic name, Broker address or Topic multicast group address.

6. The method for accessing and configuring industrial control equipment in a publish-subscribe mode with deterministic differentiation according to claim 1, characterized in that: The network manager formulates communication strategies for publish-subscribe devices and switches based on device locations, network communication link resource conditions, and device configuration information of publish-subscribe relationships, including: Real-time topics are distributed using multicast. The Writer sets the destination address of the real-time topic to the configured topic multicast group address, which is then forwarded by the network switch or router to the readers in the multicast group. For non-real-time topics, the Broker message agent forwarding method is adopted; the Writer sends the non-real-time topic to the configured Broker, and the Reader obtains the subscribed topic from the Broker; and according to the device location and network load, different Brokers are selected to load balance the traffic.

7. A deterministic publish-subscribe model industrial control equipment access and configuration system, characterized by: include: Static devices are used to send device registration requests and initial device information to the discovery server, and receive and execute the communication policy configuration of the discovery server; Programmable device for executing user-developed logic control and discovery server communication strategy configuration based on the program and configuration downloaded from the IDE; The discovery server is used to interact with static devices, authenticate static devices, and allow access to static devices that meet the authentication conditions, completing device registration. The discovery server sends a device configuration read request to the registered static device to obtain the initial device information of the static device. Used to interact with the IDE, respond to the IDE's request to register static devices and obtain their initial device information, and obtain the device configuration information of programmable devices and static devices configured by the IDE; Used to interact with the network manager, send all integrated device configuration information to the network manager, and send the communication policy configuration information sent by the network manager to all devices; The IDE is used to request the discovery server to register static devices and initial device information, and obtain the registered static devices and their initial device information; based on the obtained registered static devices and initial device information, configure the publish-subscribe communication relationship and communication QoS requirements between the programmable device and the static device, obtain the device configuration information of the programmable device and the static device, and send it to the discovery server; The network manager is used to formulate communication strategies for publishing and subscribing devices and switches based on device locations, network communication link resources, and device configuration information of the publishing and subscribing relationships; And configure the switch according to the communication strategy, and return the communication strategy configuration information to the discovery server; All devices including static devices, programmable devices and their IDEs, discovery servers, and network managers are used to perform device connection, topic association, and publish-subscribe communication according to the communication strategy configuration information.

Images