Publishing and subscribing mode industrial control equipment access and configuration method capable of distinguishing certainty

Abstract

The invention discloses a method for accessing and configuring industrial control equipment with differentiated certainty in a publishing and subscribing mode. The method comprises the following steps: a discovery server obtains initial equipment information of static equipment; the IDE requests a discovery server and obtains registered static equipment and initial equipment information of the registered static equipment; constructing device configuration information of the programmable device and the static device; the discovery server integrates all equipment configuration information and sends the information to the network manager; the network manager formulates a communication strategy for the publishing and subscribing equipment and the switch; the discovery server sends the communication strategy configuration information to all the devices; and all the devices execute device connection, Topic association and publish subscription communication according to the communication strategy configuration information. Through the method provided by the invention, the industrial control system can support flexible access and automatic configuration of equipment in the publish-subscribe mode, and the certainty of real-time information transmission and the bearing performance of non-real-time information transmission of the industrial control system in the publish-subscribe mode are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial control systems, and more particularly to a method for accessing and configuring devices in a publish-subscribe mode with distinguished determinism for industrial control systems. Background Art

[0002] With the rapid development of the industrial Internet, the demand for the integration of IT systems and OT systems has become increasingly strong, and the scope of industrial control systems has been further expanded, from the local OT-side traditional industrial control systems composed of PLC and IO to the wide range of edge computing platforms, even cloud platforms, and IT systems. The information interaction between system devices has become more and more extensive. The local and fixed modes of traditional industrial systems are limited by resources and scope and can no longer support the needs of applications. Opening up the originally isolated data information of industrial control systems and supporting flexible access and data acquisition of external devices has become the development direction of industrial control systems under the new situation.

[0003] The Publish-Subscribe model (Pub / Sub) is an asynchronous messaging model in the IT field, which has more flexible data transmission characteristics. The publisher is responsible for publishing specific topics, without caring who will receive these messages. Subscribers only care about the topics they are interested in and only receive messages from the topics they subscribe to. The publish-subscribe model can dynamically add and delete subscribers, and the publishers and subscribers associated with a topic can be changed at any time.

[0004] Applying Pub / Sub communication to industrial control systems can solve the problem of flexibility in system communication. However, since traditional industrial control systems use a fixed connection method based on device binding, the Pub / Sub communication method is not applicable. Therefore, on the one hand, it is necessary to change the device access method of the industrial control system to support Pub / Sub communication based on Topic to achieve flexible device access and data interaction. On the other hand, industrial control systems have high requirements for the real-time and reliability of industrial application data communication, while the ordinary pub / Sub communication method is mainly for non-real-time data transmission and cannot guarantee the deterministic requirements of industrial control system data.

[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] In order 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, and the discovery server authenticates the static device. For static devices that meet the authentication conditions, the device access is allowed to complete 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; the IDE configures the publish-subscribe communication relationship and communication QoS requirements between the programmable device and the static device according to the registered static device and initial device information obtained, 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 location, network communication link resource conditions, and device configuration information of the publishing and subscribing communication relationship; 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, compiled into the program configuration by the IDE, and sent 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 the device role sub, the reader Reader, the writer Writer, and the topic Topic.

[0015] The initial device information includes:

[0016] Device role information: publisher is Publisher or Pub, subscriber is Subscriber or Sub, message broker is Broker;

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

[0018] Writer information: including the writer name and related subject 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 subject 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 a communication strategy for the publish-subscribe device and the switch according to the device location, the network communication link resource status and the device configuration information of the publish-subscribe relationship, including:

[0031] For real-time topics, multicast is used for distribution. 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 and sent to the Reader 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 system for accessing and configuring industrial control equipment in a publish-subscribe mode with deterministic distinction, comprising:

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

[0035] A programmable device for executing user-developed logic control and communication strategy configuration of the discovery server according to the program and configuration downloaded by the IDE;

[0036] The discovery server is used to interact with static devices, authenticate static devices, and allow device access to static devices that meet the authentication conditions to complete 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; it 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; it is used to interact with the network manager, send all integrated device configuration information to the network manager, and send the communication strategy configuration information sent by the network manager to all devices;

[0037] IDE, 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; according to 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 resource conditions, and device configuration information of the publishing and subscribing 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 certainty 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 an industrial control device access and configuration system composed of a publish-subscribe mode that distinguishes determinism 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 that distinguishes determinism according to the present invention;

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

[0046] FIG. 4( a ) is a schematic diagram of an embodiment of the present invention for distinguishing deterministic publish-subscribe mode communication strategy Figure 1 ;

[0047] FIG. 4( 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 be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work 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 distinguishing deterministic publish-subscribe mode for industrial control systems according to the present invention;

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

[0051] Industrial equipment includes PLC, IO devices, edge devices, computers, etc. Industrial equipment is connected through the network and communicates data. PLC, as the main control unit of the industrial control system, is responsible for the operation and processing logic of the equipment within the control range. Before the PLC is officially put into operation, it is necessary to configure the system (configuration) and write and compile the application program through the user integrated development environment IDE on the computer, and then download the configured and compiled executable file to the PLC for execution. According to the degree of intelligence of the equipment, that is, whether the equipment supports programmability, it can be divided into two types. One is a static device, that is, the device function is fixed after leaving the factory and does not support programming modification. For example, for IO devices, the device information configuration (called initial device information) is set at the factory. One is a programmable device, such as PLC, edge controller, etc. The device function can support programming modification through the supporting development environment IDE, and the device information configuration can be set according to the development user's needs.

[0052] Data distribution equipment includes discovery servers, brokers, network switches, and network managers. Data distribution equipment is responsible for data forwarding and transmission. Among them, the discovery server is responsible for device discovery, registration, configuration, and management of device publishing and subscription information. It can interact with the network manager to achieve collaborative configuration management of network devices and terminal devices. Broker is an agent device for Topic message aggregation and distribution. Topic messages from the publisher are sent to Broker, and subscription requirements from the subscriber are also sent to Broker. Broker matches the published and subscribed Topics, and Broker is responsible for forwarding successfully matched Topics to the subscriber.

[0053] See also Figure 2 , a flow chart of an embodiment of a method for accessing and configuring a device in a publish-subscribe mode with distinguished determinism for an industrial control system according to the present invention, comprising:

[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 initial device information of the static device;

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

[0057] Step 204: IDE configures the communication relationship and communication QoS requirements between the programmable device and the static device based on the acquired registered device and initial device information and the communication relationship of the control application, and obtains the device configuration information of the programmable device and the static device. 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 location, network communication link resource conditions, and device configuration information of the publishing and subscribing relationship. The network manager configures the switch based on the communication strategy and returns the formulated device communication strategy configuration information to the discovery server;

[0060] Among them, real-time topics are distributed in multicast mode. The Writer sets the destination address of the real-time topic to the configured topic multicast group address, and the network switch / router performs multicast forwarding and sends it to the Reader in the multicast group.

[0061] Non-real-time topics are forwarded by Broker messages. Writer sends non-real-time topics to the configured Broker, and Reader obtains subscribed topics from Broker. Different Brokers are selected to load balance traffic according to the device location and network load.

[0062] Step 207: The discovery server sends the communication policy configuration information to each device, wherein the communication policy configuration information of the static device is directly sent down, and the programmable device needs to send the configuration information to the IDE, which is then compiled into the program configuration by the IDE and sent down 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 information inherent to static devices, and is generally related to the functions supported by the device itself. For example, for digital input devices in IO devices, the device role is publisher, contains at least one Writer, and the associated Topic is the data volume input value of this device. For quantitative output devices, the device role is subscriber, contains at least one Reader, and the associated Topic is the data volume output value of this device.

[0066] The initial equipment 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 subject information.

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

[0071] Device configuration information is the information of each device formed after the IDE configures the publish-subscribe relationship and QoS requirements. According to the application logic's demand for data communication, the user configures the publish-subscribe relationship of the Topic between each device through the IDE, and declares the required publish-subscribe cycle, the subject's real-time and reliability and other QoS requirements to form the overall device configuration information of the industrial control system's publish-subscribe. Device configuration information specifically includes:

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

[0073] Reader information: including reader name, related subject information, and subscription period.

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

[0075] Topic information: including Topic name, Topic data type, Topic length, and QoS requirements. QoS requirements include: real-time type (divided into real-time and non-real-time), reliable type (divided 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 communication strategy is generated by the algorithm calculation based on the device configuration information of the publish-subscribe relationship, the network resource usage, the 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, persistence configuration (divided into retaining the latest data, retaining all historical data, and deleting historical data after a certain period of time)

[0078] Writer QoS information: including publishing cycle, priority / time slot, reliability configuration, persistence configuration (divided into 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 strategy 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 communication strategy for distinguishing deterministic publish-subscribe mode according to the present invention, including:

[0082] The IO device acts as a Publisher and contains two Writers. Writer1 publishes Topic1 and Writer2 publishes Topic2. The edge device acts as a Subscriber and contains three Readers. Reader1 subscribes to Topic2, Reader2 subscribes to Topic3, and Reader3 subscribes to Topic4. The PLC contains two roles. As a Publisher, it contains two Writers. Writer1 publishes Topic3 ​​and Writer2 publishes Topic4. As a Subscriber, it contains two Readers. Reader1 subscribes to Topic1 and Reader2 subscribes to Topic2. The system contains two Brokers. Broker1 is responsible for forwarding Topic3 ​​and Broker2 is responsible for forwarding Topic4. Topic1 and Topic2 are real-time Topics, and Topic3 ​​and Topic4 are non-real-time Topics.

[0083] Among them, Figure 4 (a) shows the publish-subscribe communication strategy of real-time Topic2. Through the communication strategy formulated by the network manager, real-time Topic2 uses multicast to distribute data, which can improve the real-time performance of data transmission. The Reader subscribed to Topic2 is set to a multicast group. When Topic2 is published to the network, the Writer sets the destination address of Topic2 to the configured Topic2 multicast address. The network switch will copy the data packet of Topic2 according to the multicast address and forward it directly to the devices in the group (PLC and edge devices).

[0084] Figure 4(b) shows the publish-subscribe communication strategy for non-real-time Topic3 ​​and Topic4. Non-real-time Topic adopts Broker message agent forwarding. Since all Topics need to be forwarded through Broker, the network pressure of Broker is relatively large. Therefore, the present invention selects Brokers assigned to Topics for load balancing, reduces the network pressure of Broker, 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 Topic3 ​​adopts Broker1 message agent forwarding, and Topic4 adopts Broker2 message agent forwarding. Writer1 of PLC device sends Topic3 ​​to configured Broker1 according to the communication strategy formulated by the network manager, and Reader2 of edge device subscribes to Topic3 ​​from Broker1 according to the communication strategy. When Topic3 ​​is published to the network, Topic3 ​​data packet will be sent to Broker1 first, and Broker will temporarily store and manage it. When the subscription request is matched, Topic3 ​​data will be sent to Reader2 of edge device. Similarly, the processing process of Topic4 is similar to that of 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 enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be 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 will not be limited to the embodiments shown herein, but rather 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, and the discovery server authenticates the static device. For static devices that meet the authentication conditions, the device access is allowed to complete 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; the IDE configures the publish-subscribe communication relationship and communication QoS requirements between the programmable device and the static device according to the registered static device and initial device information obtained, 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 the publishing and subscribing devices and switches based on the device location, network communication link resource conditions, and device configuration information of the publishing and subscribing communication relationship; And configure the switch according to the communication strategy, and return the formulated 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, compiled into the program configuration by the IDE, and sent to the programmable device; All devices perform device connection, Topic association and publish-subscribe communication according to the communication strategy configuration information.

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

3. According to claim 1, a method for accessing and configuring industrial control equipment in a publish-subscribe mode with distinguishing determinism is characterized in that: The initial device information includes: Device role information: publisher is Publisher or Pub, subscriber is Subscriber or Sub, message broker is Broker; Reader information: including reader name and related subject information; Writer information: including the writer name and related subject information; Topic information: including Topic name, Topic data type, and Topic length.

4. According to claim 1, a method for accessing and configuring industrial control equipment in a publish-subscribe mode with distinguishing determinism is 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 subject 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. According to claim 1, a method for accessing and configuring industrial control equipment in a publish-subscribe mode that distinguishes determinism is 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. According to claim 1, a method for accessing and configuring industrial control equipment in a publish-subscribe mode with distinguishing determinism is characterized in that: The network manager formulates a communication strategy for the publish-subscribe device and the switch according to the device location, the network communication link resource status and the device configuration information of the publish-subscribe relationship, including: For real-time topics, multicast is used for distribution. 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 and sent to the Reader 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 system for accessing and configuring industrial control equipment in a publish-subscribe mode that distinguishes determinism, characterized in that: include: Static device, used to send device registration request and initial device information to the discovery server, receive and execute the communication policy configuration of the discovery server; A programmable device for executing user-developed logic control and communication strategy configuration of the discovery server according to the program and configuration downloaded by the IDE; The discovery server is used to interact with the static device, authenticate the static device, and allow the device to access and complete the device registration for the static device that meets the authentication conditions; 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 strategy configuration information sent by the network manager to all devices; IDE, 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; according to 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 resource conditions, and device configuration information of the publishing and subscribing relationship; And configure the switch according to the communication strategy, and return the formulated 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.

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