VPDN-based multi-user multiplexing and flow-saving industrial data acquisition system

Abstract

The invention discloses a VPDN-based multi-user multiplexing and flow-saving industrial data acquisition system, and the system comprises a communication access module which is used for accessing a VPDN through a 4G communication terminal and building a southbound channel; the point location model module is used for generating point location information by the middle platform; the flower name mapping module is used for establishing mapping and synchronization of discrete point locations and flower names; the user structure module is used for the gateway to create a user table, an equipment table and a point location table; the acquisition scheduling module is used for generating and issuing an acquisition task; the data processing module is used for collecting point location data and constructing a message; the encryption uploading module is used for encrypting the message and then uploading the encrypted message; the decryption and restoration module is used for analyzing the message and restoring the point location by the middle station; and the user initialization module is used for synchronizing structure configuration during user access. The reusability and the transmission efficiency of the data acquisition system are improved.

Description

Technical Field

[0001] The present invention relates to the field of industrial Internet and data acquisition technology, and in particular to an industrial data acquisition system based on VPDN for multi-user multiplexing and flow saving. Background Art

[0002] With the development of information technology, industrial control systems are gradually evolving towards informatization and intelligence. With the widespread adoption of the Internet of Things (IoT) architecture, industrial automation systems are increasingly adopting communication mechanisms that integrate Internet protocols. Industrial gateways, key components connecting field devices with remote servers, are commonly configured with the MQTT protocol for northbound interfaces and the Modbus protocol for southbound interfaces. MQTT, based on a publish / subscribe model, is suitable for low-bandwidth, high-latency, and unstable network environments. Modbus, based on a client / server model, is widely used for data exchange between industrial devices.

[0003] In traditional architectures, industrial gateways are usually deployed near data acquisition interfaces and communicate with southbound devices through wired links. This deployment method has certain advantages in terms of stability, but it also brings a significant cost burden. On the one hand, to support edge computing functions, industrial gateways are equipped with higher computing performance, and the hardware cost is much higher than that of general data forwarding equipment. On the other hand, in a large number of practical applications, the data throughput of southbound collection points is far lower than the processing capacity limit of industrial gateways, computing resources cannot be fully utilized, and there is a lack of computing power coordination mechanism between different industrial gateways, resulting in prominent resource waste problems. In addition, current data acquisition systems generally have the characteristics of a large number of discrete points and a low data update frequency. If a complete message structure is still used for each transmission, a large amount of redundant traffic will be generated, increasing communication costs.

[0004] In a multi-user shared network environment, although the existing MQTT protocol supports user isolation mechanisms, it is mostly limited to the northbound interface level. When an industrial gateway is connected to the southbound devices of multiple users at the same time, the traditional mechanism is difficult to achieve southbound data isolation by user dimension, which easily causes cross-data access. Therefore, the existing data acquisition system still has room for technical improvement in reducing access costs, saving traffic overhead and achieving southbound user isolation.

[0005] Therefore, how to provide an industrial data acquisition system based on VPDN with multi-user multiplexing and traffic saving is an urgent problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] One objective of the present invention is to provide a multi-user multiplexing and data-saving industrial data acquisition system based on VPDN. This system establishes a virtual private network (VPN) based on the VPDN protocol to establish a remote data channel between 4G communication terminals and a centralized industrial gateway. It utilizes a name compression mechanism to reduce message lengths at discrete points, and designs a multi-user classification management structure to achieve user isolation and classified upload of southbound data. This system offers the advantages of low deployment cost, minimal data communication traffic, and strong support for user isolation.

[0007] The multi-user multiplexing and traffic saving industrial data acquisition system based on VPDN according to an embodiment of the present invention includes: The communication access module is used to access the virtual private network based on the VPDN protocol through a 4G communication terminal, obtain the VPN address and establish a southbound channel with the industrial gateway; The point model module is used to establish the point model in the middle platform and generate the point name, data type, initial value and discrete identifier; The flower name mapping module is used by the middle platform to generate flower names for discrete points, establish mapping relationships and synchronize them to 4G communication terminals; User structure module, used by the industrial gateway to create user tables, device tables, and point tables, recording user identification, device identification, and point information; The collection scheduling module is used by the industrial gateway to traverse the user table, search the device table and point table, generate collection tasks and send them to the 4G communication terminal; The data processing module is used by the 4G communication terminal to collect point data, determine changes, and construct messages using flower names or point names; The encrypted upload module is used by the industrial gateway to receive and classify data messages, encrypt them according to the user key, and upload them to the middle platform through the MQTT protocol; The decryption and restoration module is used to decrypt data messages in the middle station, restore the point name according to the mapping relationship and parse the data content; The user initialization module is used to create user directories, initialize structures and complete synchronization when new users are added.

[0008] Optionally, modules can be connected using the following methods: S1. 4G communication terminals access a virtual private network based on the VPDN protocol and are located in the same VPN segment as the industrial gateway to establish a southbound channel. S2. The middle station establishes a point model, including the point name, data type, initial value and discrete identifier; S3. The middle station generates hexadecimal flower names for discrete points, establishes a mapping relationship between the points and flower names, and sends it to the 4G communication terminal. The 4G communication terminal sends back confirmation information, and the middle station completes the synchronization after the comparison is consistent; S4. The industrial gateway creates a user table, a device table, and a point table as user data structures. S5. The industrial gateway traverses the user table, searches the corresponding device table and location table, determines the southbound device and location of each user, and initiates a collection request to the 4G communication terminal. S6 and 4G communication terminals collect point values and determine changes. Discrete points with unchanged values are represented by flower names, while other points retain their point names and generate data packets. S7. The industrial gateway receives data packets, classifies them by user, encrypts them with user keys, and uploads them to the middle platform via the MQTT protocol. S8. The middle station uses the user key to decrypt the message, restores the point name according to the mapping relationship, and completes the user data parsing and storage; S9. When a new user accesses, the middle platform and the industrial gateway create user directories under the local path, initialize the user table, device table and point table, and synchronize the configuration information.

[0009] Optionally, the middle platform is the server-side control platform in the system, responsible for unified management of point model configuration, flower name synchronization, user information initialization, data parsing and storage. The industrial gateway and the middle platform are deployed on the same hardware device, and complete task division and data interaction through internal bus or local loopback address communication.

[0010] Optionally, the user table records user identification, user name and user key, the device table records device identification, device name, VPN address and port number, and the point table records device identification, point name, register address, data type and description information.

[0011] Optionally, the S3 specifically includes: S31, the middle station generates a flower name for the point with a discrete identifier of 1 in the point model, and the flower name consists of 4 hexadecimal characters; S32. The middle station establishes a one-to-one correspondence between the point name and the flower name for each discrete point, forming a mapping relationship table; S33, the middle station sends the mapping relationship table to the 4G communication terminal; S34, the 4G communication terminal receives the mapping relationship table and completes the binding operation between the flower name and the point; S35 and 4G communication terminals transmit the binding results back to the middle station; S36. The middle platform compares the returned results with the original mapping relationship table, and completes the flower name synchronization when the field contents are consistent.

[0012] Optionally, the S5 specifically includes: S51, the industrial gateway traverses the user table and extracts the user ID; S52, filtering device records with the same device ID in the device table according to the user ID; S53, searching for the corresponding point record in the point table according to the device identifier, and extracting the point name and data type; S54, composing a collection task list by combining the user ID, device ID, point name and data type; S55. The industrial gateway sends a collection request instruction to the 4G communication terminal through the VPN link based on the collection task list.

[0013] Optionally, the S6 specifically includes: S61, the 4G communication terminal collects point values according to the device identifier and point name included in the collection task list; S62, the 4G communication terminal compares the current point value with the last uploaded value; S63. When the point is discrete and the current value is the same as the previous value, the flower name is used as the identifier; S64. When the point is non-discrete, or the current value is different from the previous value, the point name is used as the identifier; S65, 4G communication terminal constructs data message based on identification type, point value and timestamp.

[0014] Optionally, the S7 specifically includes: S71. The industrial gateway receives a data message uploaded by the 4G communication terminal and reads a user identification field in the data message. S72. The industrial gateway classifies the data packets according to the user identifiers and establishes data cache queues corresponding to the users. S73. The industrial gateway searches the user table for a record that matches the user ID and extracts the user key field. S74. The industrial gateway performs an encryption operation on the data message in each cache queue using the corresponding user key to generate an independent encrypted message; S75. The industrial gateway sends each encrypted message to the middle station through the MQTT protocol according to the topic path matched by the user identifier.

[0015] Optionally, the S8 specifically includes: S81, the middle station receives the data message uploaded by the MQTT protocol and extracts the user identification field in the data message; S82. The middle platform searches the user table for a record that matches the user ID and extracts the user key field. S83, the middle station calls the user key to decrypt the data message and obtain the plaintext content; S84. The middle platform parses the identification field in the plain text content and determines whether the identification field is a flower name or a location name; S85. When the identification field is a flower name, the middle station searches for a mapping item that matches the flower name in the flower name mapping relationship table to obtain the point name; S86, the middle station extracts the point value and timestamp based on the identification field or the restored point name, and constructs the point data record; S87. The middle platform classifies the point data records according to the user ID and writes them into the specified data table structure in the database.

[0016] Optionally, the S9 specifically includes: S91. The middle platform creates a user directory for the new user in the file system; S92, the middle station initializes the user table, device table and point table in the user directory, and writes the field structure and header information; S93: The industrial gateway receives a new user access request and creates a user directory in the file system that is named the same as the one in the middle platform. S94. The industrial gateway initializes the user table, device table, and point table in the user directory. The field structure is consistent with that of the middle platform. S95, the middle platform and the industrial gateway perform configuration comparison operations, verify the user directory structure, table structure and configuration information item by item, and complete the initialization data synchronization.

[0017] The beneficial effects of the present invention are: In existing industrial data acquisition systems, industrial gateways are typically deployed at the acquisition site, connected to southbound devices via wired connections, and using the MQTT and Modbus protocols for north-south communication. Although this model has a certain degree of stability and maturity, due to the generally high computing performance of industrial gateways, it is prone to idle resources and high construction costs in scenarios where they are only used to forward collected data. In addition, when multiple users share an industrial gateway, the traditional architecture only supports user isolation on the northbound interface. Southbound data acquisition cannot be managed by user classification, and there is a risk of user data mixing. At the same time, in scenarios dominated by discrete points, the data update frequency is low, and continuously uploading complete messages will lead to a waste of communication traffic.

[0018] In response to the above problems, the present invention proposes an industrial data acquisition system based on VPDN with multi-user multiplexing and traffic saving. By accessing the virtual private network built by the VPDN protocol through 4G communication terminals, a remote data channel is established with the centrally deployed industrial gateway, replacing the traditional distributed gateway deployment method, which significantly reduces the hardware cost. The system introduces the middle-end point model and flower name mapping mechanism, and uses hexadecimal flower names to represent discrete points, reducing the length of the point field in the message, thereby effectively saving upload traffic. The industrial gateway conducts structured management of different user data by constructing user tables, device tables and point tables. The acquisition process generates data messages according to user classification and uploads them encrypted. The middle-end decrypts and restores the data based on the mapping relationship to ensure that the data is isolated and processed by user during the acquisition, transmission and parsing process.

[0019] By building a virtual private channel, compressing message content, and supporting southbound and northbound multi-user multiplexing mechanisms, the system improves resource utilization and reduces operation and maintenance costs while ensuring communication reliability. It solves the technical bottlenecks of traditional data acquisition systems in terms of high deployment costs, severe traffic waste, and mixed user data. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 This is a flow chart of the industrial data acquisition system based on VPDN for multi-user multiplexing and traffic saving proposed by the present invention; Figure 2 This is a schematic diagram of the system architecture of the VPDN-based multi-user multiplexing and traffic-saving industrial data acquisition system proposed by the present invention; Figure 3 This is a southbound channel connection diagram of the industrial data acquisition system based on VPDN for multi-user multiplexing and traffic saving proposed by the present invention; Figure 4 This is a structural diagram of the multi-user multiplexing mechanism of the industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving proposed by the present invention; Figure 5 This is a flowchart of southbound device data acquisition for the industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving proposed by the present invention; Figure 6 This is a flowchart of northbound data upload for the industrial data acquisition system with multi-user multiplexing and traffic saving based on VPDN proposed by the present invention. DETAILED DESCRIPTION

[0021] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0022] refer to Figure 1-6 , a VPDN-based multi-user multiplexing and traffic-saving industrial data acquisition system, including: The communication access module is used to access the virtual private network based on the VPDN protocol through a 4G communication terminal, obtain the VPN address and establish a southbound channel with the industrial gateway; The point model module is used to establish the point model in the middle platform and generate the point name, data type, initial value and discrete identifier; The flower name mapping module is used by the middle platform to generate flower names for discrete points, establish mapping relationships and synchronize them to 4G communication terminals; User structure module, used by the industrial gateway to create user tables, device tables, and point tables, recording user identification, device identification, and point information; The collection scheduling module is used by the industrial gateway to traverse the user table, search the device table and point table, generate collection tasks and send them to the 4G communication terminal; The data processing module is used by the 4G communication terminal to collect point data, determine changes, and construct messages using flower names or point names; The encrypted upload module is used by the industrial gateway to receive and classify data messages, encrypt them according to the user key, and upload them to the middle platform through the MQTT protocol; The decryption and restoration module is used to decrypt data messages in the middle station, restore the point name according to the mapping relationship and parse the data content; The user initialization module is used to create user directories, initialize structures and complete synchronization when new users are added.

[0023] The present invention forms a complete industrial data acquisition system functional link by constructing functional modules such as communication access, point model, flower name mapping, user structure, acquisition scheduling, data processing, encryption upload, decryption and restoration, and user initialization, and realizes a system-level integrated design with user isolation, traffic saving, and unified equipment management.

[0024] In this embodiment, the modules are connected through the following methods: S1. 4G communication terminals access a virtual private network based on the VPDN protocol and are located in the same VPN segment as the industrial gateway to establish a southbound channel. S2. The middle station establishes a point model, including the point name, data type, initial value and discrete identifier; S3. The middle station generates hexadecimal flower names for discrete points, establishes a mapping relationship between the points and flower names, and sends it to the 4G communication terminal. The 4G communication terminal sends back confirmation information, and the middle station completes the synchronization after the comparison is consistent; S4. The industrial gateway creates a user table, a device table, and a point table as user data structures. S5. The industrial gateway traverses the user table, searches the corresponding device table and location table, determines the southbound device and location of each user, and initiates a collection request to the 4G communication terminal. S6 and 4G communication terminals collect point values and determine changes. Discrete points with unchanged values are represented by flower names, while other points retain their point names and generate data packets. S7. The industrial gateway receives data packets, classifies them by user, encrypts them with user keys, and uploads them to the middle platform via the MQTT protocol. S8. The middle station uses the user key to decrypt the message, restores the point name according to the mapping relationship, and completes the user data parsing and storage; S9. When a new user accesses, the middle platform and the industrial gateway create user directories under the local path, initialize the user table, device table and point table, and synchronize the configuration information.

[0025] The present invention realizes the functional connection between modules through specific processes, establishes a full-process control mechanism for industrial data collection based on the VPDN network environment, and ensures the stability and hierarchical controllability of the entire process from southbound device collection to data reporting and analysis.

[0026] In this embodiment, the middle platform is the server-side control platform in the system, which is responsible for unified management of point model configuration, flower name synchronization, user information initialization, data parsing and storage. The industrial gateway and the middle platform are deployed on the same hardware device, and complete task division and data interaction through internal bus or local loopback address communication.

[0027] The present invention deploys the middle platform and the industrial gateway on the same hardware device, and completes command scheduling and data flow through bus communication. While ensuring functional isolation, it significantly improves device integration and reduces hardware deployment costs and operation and maintenance complexity.

[0028] In this embodiment, the user table records user identification, user name and user key, the device table records device identification, device name, VPN address and port number, and the point table records device identification, point name, register address, data type and description information.

[0029] The present invention standardizes the data organization mode under the user isolation mechanism by uniformly defining the field structures of the user table, device table and point table, thereby improving the independence of user management, the security of data access and the retrieval efficiency of the data structure.

[0030] In this embodiment, S3 specifically includes: S31, the middle station generates a flower name for the point with a discrete identifier of 1 in the point model, and the flower name consists of 4 hexadecimal characters; S32. The middle station establishes a one-to-one correspondence between the point name and the flower name for each discrete point, forming a mapping relationship table; S33, the middle station sends the mapping relationship table to the 4G communication terminal; S34, the 4G communication terminal receives the mapping relationship table and completes the binding operation between the flower name and the point; S35 and 4G communication terminals transmit the binding results back to the middle station; S36. The middle platform compares the returned results with the original mapping relationship table, and completes the flower name synchronization when the field contents are consistent.

[0031] The present invention constructs a compact data representation for discrete points through a synchronization mechanism of flower name generation and mapping relationship. Combined with the flower name consistency confirmation process, it effectively avoids collection mistransmission caused by mapping errors and improves the reliability of discrete point data compression and recognition.

[0032] In this embodiment, the S5 specifically includes: S51, the industrial gateway traverses the user table and extracts the user ID; S52, filtering device records with the same device ID in the device table according to the user ID; S53, searching for the corresponding point record in the point table according to the device identifier, and extracting the point name and data type; S54, composing a collection task list by combining the user ID, device ID, point name and data type; S55. The industrial gateway sends a collection request instruction to the 4G communication terminal through the VPN link based on the collection task list.

[0033] The present invention clarifies the relationship between the equipment and points bound to each user through the joint query mechanism of the user table, the equipment table and the point table, realizes the accurate matching and scheduling generation of data acquisition tasks in a multi-user environment, and enhances the scalability and scheduling control accuracy of the system.

[0034] In this embodiment, S6 specifically includes: S61, the 4G communication terminal collects point values according to the device identifier and point name included in the collection task list; S62, the 4G communication terminal compares the current point value with the last uploaded value; S63. When the point is discrete and the current value is the same as the previous value, the flower name is used as the identifier; S64. When the point is non-discrete, or the current value is different from the previous value, the point name is used as the identifier; S65, 4G communication terminal constructs data message based on identification type, point value and timestamp.

[0035] The present invention uses a selective use mechanism of flower names and point names to dynamically judge and switch identification modes during the data collection process, thereby realizing a message compression strategy based on point changes, reducing message redundancy, and improving resource utilization efficiency of data transmission.

[0036] In this embodiment, the S7 specifically includes: S71. The industrial gateway receives a data message uploaded by the 4G communication terminal and reads a user identification field in the data message. S72. The industrial gateway classifies the data packets according to the user identifiers and establishes data cache queues corresponding to the users. S73. The industrial gateway searches the user table for a record that matches the user ID and extracts the user key field. S74. The industrial gateway performs an encryption operation on the data message in each cache queue using the corresponding user key to generate an independent encrypted message; S75. The industrial gateway sends each encrypted message to the middle station through the MQTT protocol according to the topic path matched by the user identifier.

[0037] The present invention adopts an encrypted upload mechanism classified by user, encapsulates the data of each user into an independent ciphertext message, and transmits it to the middle platform by matching the MQTT topic path, thereby realizing encryption isolation of the data upload process and ensuring communication security in a multi-user environment.

[0038] In this embodiment, the S8 specifically includes: S81, the middle station receives the data message uploaded by the MQTT protocol and extracts the user identification field in the data message; S82. The middle platform searches the user table for a record that matches the user ID and extracts the user key field. S83, the middle station calls the user key to decrypt the data message and obtain the plaintext content; S84. The middle platform parses the identification field in the plain text content and determines whether the identification field is a flower name or a location name; S85. When the identification field is a flower name, the middle station searches for a mapping item that matches the flower name in the flower name mapping relationship table to obtain the point name; S86, the middle station extracts the point value and timestamp based on the identification field or the restored point name, and constructs the point data record; S87. The middle platform classifies the point data records according to the user ID and writes them into the specified data table structure in the database.

[0039] The present invention realizes the complete restoration and classified storage of uploaded data by the middle and end ends through the process of decrypting messages, restoring flower names and parsing points, constructs a parsing mechanism based on dual attribution of users and points, and ensures data consistency and classification accuracy.

[0040] In this embodiment, the S9 specifically includes: S91. The middle platform creates a user directory for the new user in the file system; S92, the middle station initializes the user table, device table and point table in the user directory, and writes the field structure and header information; S93: The industrial gateway receives a new user access request and creates a user directory in the file system that is named the same as the one in the middle platform. S94. The industrial gateway initializes the user table, device table, and point table in the user directory. The field structure is consistent with that of the middle platform. S95, the middle platform and the industrial gateway perform configuration comparison operations, verify the user directory structure, table structure and configuration information item by item, and complete the initialization data synchronization.

[0041] The present invention realizes the consistent deployment of new user directory structure and configuration information through the dual-end synchronous initialization mechanism of the middle platform and the industrial gateway in the file system, ensures the synchronization and structural integrity of the new user access process, and supports the dynamic expansion capability of users.

[0042] Example 1: In order to verify the feasibility of the present invention in implementation, the present invention is applied to the networking deployment of an industrial data acquisition system. The system accesses the VPDN private network through a 4G communication terminal to build a southbound communication channel, and centrally deploys an industrial gateway and a middle-end functional module on the server side to achieve unified management and control of southbound devices and data collection. During the system deployment process, an IoT private network SIM card provided by the operator is used, so that the 4G communication terminal automatically enters the preset VPN segment after dialing, thereby realizing communication with the industrial gateway based on IP direct connection, without the need to deploy a physical wired channel.

[0043] On the server side, the middle platform establishes a point model and generates hexadecimal flower names for points with discrete identifiers. The corresponding mapping relationship between the generated points and the flower names is sent by the middle platform to the 4G communication terminal through the MQTT protocol. After the communication terminal sends back the confirmation information, the middle platform performs a consistency comparison and completes the synchronization after confirming that the flower names match.

[0044] The industrial gateway builds a user data structure and creates a user table, device table, and point table under the local path. The user table contains user ID, user name, and user key; the device table contains device ID, device name, VPN address, and port number; the point table contains device ID, point name, register address, data type, and description information. The gateway program determines the collection equipment and point configuration of each user by traversing the user table and checking the device table and point table in parallel.

[0045] During the collection process, the 4G communication terminal processes the collected values according to the content of the point table. If the point is discrete and the value has not changed, the flower name is used instead of the original point name to construct the message. If it is a non-discrete point or the value has changed, the point name is retained. After the industrial gateway receives the data message, it is classified according to the user ID, encrypted with the user key, and uploaded to the middle platform through the MQTT protocol.

[0046] After receiving the encrypted message, the middle station uses the corresponding user key to decrypt the data and restore the point name based on the flower name mapping relationship. After the parsing is completed, the data is stored in the user data table to achieve effective isolation and management of the collected data. In the entire process, the industrial gateway and the middle station are deployed on the same hardware device and communicate through the local loopback address, reducing deployment costs and system complexity.

[0047] Under the multi-user reuse mechanism, when a new user accesses, both the middleware and the industrial gateway create a user directory in the local path and initialize the user table, device table, and point table. The gateway program loops through the data collection and classified upload process by user. All data is independently encrypted and classified by user between the gateway and the middleware, ensuring data isolation, preventing data contamination, and meeting industrial data security requirements.

[0048] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. The multi-user multiplexing and traffic saving industrial data acquisition system based on VPDN is characterized by: include: The communication access module is used to access the virtual private network based on the VPDN protocol through a 4G communication terminal, obtain the VPN address and establish a southbound channel with the industrial gateway; The point model module is used to establish the point model in the middle platform and generate the point name, data type, initial value and discrete identifier; The flower name mapping module is used by the middle platform to generate flower names for discrete points, establish mapping relationships and synchronize them to 4G communication terminals; User structure module, used by the industrial gateway to create user tables, device tables, and point tables, recording user identification, device identification, and point information; The collection scheduling module is used by the industrial gateway to traverse the user table, search the device table and point table, generate collection tasks and send them to the 4G communication terminal; The data processing module is used by the 4G communication terminal to collect point data, determine changes, and construct messages using flower names or point names; The encrypted upload module is used by the industrial gateway to receive and classify data messages, encrypt them according to the user key, and upload them to the middle platform through the MQTT protocol; The decryption and restoration module is used to decrypt data messages in the middle station, restore the point name according to the mapping relationship and parse the data content; The user initialization module is used to create user directories, initialize structures and complete synchronization when new users are added.

2. The VPDN-based multi-user multiplexing and traffic-saving industrial data acquisition system according to claim 1 is characterized in that: The modules are implemented as follows: S1. 4G communication terminals access a virtual private network based on the VPDN protocol and are located in the same VPN segment as the industrial gateway to establish a southbound channel. S2. The middle station establishes a point model, including the point name, data type, initial value and discrete identifier; S3. The middle station generates hexadecimal flower names for discrete points, establishes a mapping relationship between the points and flower names, and sends it to the 4G communication terminal. The 4G communication terminal sends back confirmation information, and the middle station completes the synchronization after the comparison is consistent; S4. The industrial gateway creates a user table, a device table, and a point table as user data structures. S5. The industrial gateway traverses the user table, searches the corresponding device table and location table, determines the southbound device and location of each user, and initiates a collection request to the 4G communication terminal. S6 and 4G communication terminals collect point values and determine changes. Discrete points with unchanged values are represented by flower names, while other points retain their point names and generate data packets. S7. The industrial gateway receives data packets, classifies them by user, encrypts them with user keys, and uploads them to the middle platform via the MQTT protocol. S8. The middle station uses the user key to decrypt the message, restores the point name according to the mapping relationship, and completes the user data parsing and storage; S9. When a new user accesses, the middle platform and the industrial gateway create user directories under the local path, initialize the user table, device table and point table, and synchronize the configuration information.

3. The VPDN-based multi-user multiplexing and traffic-saving industrial data acquisition system according to claim 2 is characterized in that: The middle platform is the server-side control platform in the system, responsible for unified management of point model configuration, flower name synchronization, user information initialization, data parsing and storage. The industrial gateway and the middle platform are deployed on the same hardware device, and complete task division and data interaction through internal bus or local loopback address communication.

4. The industrial data acquisition system with multi-user multiplexing and traffic saving based on VPDN according to claim 2 is characterized in that: The user table records user identification, user name and user key, the device table records device identification, device name, VPN address and port number, and the point table records device identification, point name, register address, data type and description information.

5. The multi-user multiplexing and traffic saving industrial data acquisition system based on VPDN according to claim 2 is characterized in that: The S3 specifically includes: S31, the middle station generates a flower name for the point with a discrete identifier of 1 in the point model, and the flower name consists of 4 hexadecimal characters; S32. The middle station establishes a one-to-one correspondence between the point name and the flower name for each discrete point, forming a mapping relationship table; S33, the middle station sends the mapping relationship table to the 4G communication terminal; S34, the 4G communication terminal receives the mapping relationship table and completes the binding operation between the flower name and the point; S35 and 4G communication terminals transmit the binding results back to the middle station; S36. The middle platform compares the returned results with the original mapping relationship table, and completes the flower name synchronization when the field contents are consistent.

6. The multi-user multiplexing and traffic saving industrial data acquisition system based on VPDN according to claim 2 is characterized in that: The S5 specifically includes: S51, the industrial gateway traverses the user table and extracts the user ID; S52, filtering device records with the same device ID in the device table according to the user ID; S53, searching for the corresponding point record in the point table according to the device identifier, and extracting the point name and data type; S54, composing a collection task list by combining the user ID, device ID, point name and data type; S55. The industrial gateway sends a collection request instruction to the 4G communication terminal through the VPN link based on the collection task list.

7. The industrial data acquisition system with multi-user multiplexing and traffic saving based on VPDN according to claim 2 is characterized in that: The S6 specifically includes: S61, the 4G communication terminal collects point values according to the device identifier and point name included in the collection task list; S62, the 4G communication terminal compares the current point value with the last uploaded value; S63. When the point is discrete and the current value is the same as the previous value, the flower name is used as the identifier; S64. When the point is non-discrete, or the current value is different from the previous value, the point name is used as the identifier; S65, 4G communication terminal constructs data message based on identification type, point value and timestamp.

8. The VPDN-based multi-user multiplexing and traffic-saving industrial data acquisition system according to claim 2 is characterized in that: The S7 specifically includes: S71. The industrial gateway receives a data message uploaded by the 4G communication terminal and reads a user identification field in the data message. S72. The industrial gateway classifies the data packets according to the user identifiers and establishes data cache queues corresponding to the users. S73. The industrial gateway searches the user table for a record that matches the user ID and extracts the user key field. S74. The industrial gateway performs an encryption operation on the data message in each cache queue using the corresponding user key to generate an independent encrypted message; S75. The industrial gateway sends each encrypted message to the middle station through the MQTT protocol according to the topic path matched by the user identifier.

9. The multi-user multiplexing and traffic saving industrial data acquisition system based on VPDN according to claim 2 is characterized in that: The S8 specifically includes: S81, the middle station receives the data message uploaded by the MQTT protocol and extracts the user identification field in the data message; S82. The middle platform searches the user table for a record that matches the user ID and extracts the user key field. S83, the middle station calls the user key to decrypt the data message and obtain the plaintext content; S84. The middle platform parses the identification field in the plain text content and determines whether the identification field is a flower name or a location name; S85. When the identification field is a flower name, the middle station searches for a mapping item that matches the flower name in the flower name mapping relationship table to obtain the point name; S86, the middle station extracts the point value and timestamp based on the identification field or the restored point name, and constructs the point data record; S87. The middle platform classifies the point data records according to the user ID and writes them into the specified data table structure in the database.

10. The VPDN-based multi-user multiplexing and traffic saving industrial data acquisition system according to claim 2, characterized in that: The S9 specifically includes: S91. The middle platform creates a user directory for the new user in the file system; S92, the middle station initializes the user table, device table and point table in the user directory, and writes the field structure and header information; S93: The industrial gateway receives a new user access request and creates a user directory in the file system that is named the same as the one in the middle platform. S94. The industrial gateway initializes the user table, device table, and point table in the user directory. The field structure is consistent with that of the middle platform. S95, the middle platform and the industrial gateway perform configuration comparison operations, verify the user directory structure, table structure and configuration information item by item, and complete the initialization data synchronization.

Images