Industrial data acquisition system based on vpdn multi-user multiplexing and traffic saving

Abstract

The application discloses an industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving, comprising a communication access module, a point site model module, a name mapping module, a user structure module, an acquisition scheduling module, a data processing module, an encryption uploading module, a decryption restoration module and a user initialization module.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial internet and data acquisition, and particularly relates to an industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving. BACKGROUND

[0002] With the development of information technology, industrial control systems are gradually evolving towards informatization and intelligentization. Under the background of the wide promotion of the Internet of Things architecture, industrial automation systems widely use communication mechanisms that integrate Internet protocols. Industrial gateways, as key components connecting field devices and remote servers, are commonly configured to use MQTT protocol for northbound interface and Modbus protocol for southbound interface. MQTT protocol is based on the publish / subscribe model and is suitable for low-bandwidth, high-latency and unstable network environments. Modbus protocol is based on the client / server model and is widely used for data interaction between industrial devices.

[0003] In the traditional architecture, industrial gateways are usually deployed near data acquisition interfaces and communicate with southbound devices through wired links. This deployment method has certain advantages in stability, but also brings 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 devices. On the other hand, in a large number of practical applications, the data throughput of southbound acquisition points is much lower than the upper limit of the processing capacity of industrial gateways, and the computing resources cannot be fully utilized. In addition, there is a lack of computing power coordination mechanism among different industrial gateways, resulting in a prominent waste of resources. Furthermore, the current data acquisition system generally has the characteristics of a large number of discrete points and low data update frequency. If the complete message structure is still used for each transmission, a large amount of redundant traffic will be generated, increasing the communication cost.

[0004] In a multi-user shared network environment, although the existing MQTT protocol supports user isolation mechanism, it is mostly limited to the northbound interface level. When an industrial gateway simultaneously accesses southbound devices of multiple users, the traditional mechanism cannot realize the isolation of southbound data by user dimension, which easily causes cross-access of data. Therefore, there is still room for technical improvement in reducing access cost, saving traffic overhead and realizing southbound user isolation in the existing data acquisition system.

[0005] Therefore, how to provide an industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving is a problem that those skilled in the art need to solve. SUMMARY

[0006] One purpose of the present application is to propose a VPDN-based multi-user multiplexing and traffic-saving industrial data acquisition system.

[0007] The VPDN-based multi-user multiplexing and traffic-saving industrial data acquisition system according to the embodiments of the present application comprises:

[0008] A communication access module is configured to access a virtual private network based on a VPDN protocol through a 4G communication terminal, acquire a VPN address, and establish a southbound channel with an industrial gateway;

[0009] A point site model module is configured to establish a point site model by a middle station, generate a point site name, a data type, an initial value, and a discrete type identifier;

[0010] A flower name mapping module is configured to generate a flower name for a discrete point site by the middle station, establish a mapping relationship, and synchronize to the 4G communication terminal;

[0011] A user structure module is configured to create a user table, a device table, and a point site table by the industrial gateway, and record a user identifier, a device identifier, and point site information;

[0012] An acquisition scheduling module is configured to traverse the user table by the industrial gateway, search the device table and the point site table, generate an acquisition task, and deliver the acquisition task to the 4G communication terminal;

[0013] A data processing module is configured to acquire point site data by the 4G communication terminal, judge a change, and construct a message by using a flower name or a point site name;

[0014] An encrypted uploading module is configured to receive and classify data messages by the industrial gateway, encrypt according to a user key, and upload to the middle station through an MQTT protocol;

[0015] A decryption and restoration module is configured to decrypt data messages by the middle station, restore a point site name according to a mapping relationship, and analyze data content;

[0016] A user initialization module is configured to create a user directory by the middle station and the industrial gateway respectively when a new user accesses, initialize a structure, and complete synchronization.

[0017] Optionally, the modules are realized through the following methods:

[0018] S1, a 4G communication terminal accesses a virtual private network based on a VPDN protocol, is in the same VPN network segment as an industrial gateway, and establishes a southbound channel;

[0019] S2, the middle station establishes a point model, including point name, data type, initial value and discrete type identification;

[0020] S3, the middle station generates a hexadecimal name for the discrete point, establishes a mapping relationship between the point and the name, and issues it to the 4G communication terminal. The 4G communication terminal returns confirmation information, and the middle station compares and synchronizes after consistency;

[0021] S4, the industrial gateway creates a user table, a device table and a point table as a user data structure;

[0022] S5, the industrial gateway traverses the user table, finds the corresponding device table and point table, determines the southbound device and point of each user, and initiates a collection request to the 4G communication terminal;

[0023] S6, the 4G communication terminal collects point value and judges the change. The discrete point with unchanged value is represented by the name, and other points retain the point name to generate a data packet;

[0024] S7, the industrial gateway receives the data packet, classifies it by user, encrypts it using the user key, and uploads it to the middle station through the MQTT protocol;

[0025] S8, the middle station decrypts the message using the user key, restores the point name according to the mapping relationship, and completes user data analysis and storage;

[0026] S9, when a new user is added, the middle station and the industrial gateway create a user directory under the local path, initialize the user table, the device table and the point table, and synchronize the configuration information.

[0027] Optionally, the middle station is a server-side control platform in the system, responsible for unified management of point model configuration, name synchronization, user information initialization, data analysis and storage. The industrial gateway and the middle station are deployed on the same hardware device, and the task division and data interaction are completed through internal bus or local loop address communication.

[0028] 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.

[0029] Optionally, S3 specifically includes:

[0030] S31, the middle station generates a name for the point with discrete type identification 1 in the point model. The name consists of 4 hexadecimal characters;

[0031] S32, the middle station establishes a one-to-one correspondence between the point name and the name for each discrete point to form a mapping relationship table;

[0032] S33, the middle station distributes the mapping relationship table to the 4G communication terminal;

[0033] S34, the 4G communication terminal receives the mapping relationship table and completes the binding operation of the nickname and the point;

[0034] S35, the 4G communication terminal returns the binding result to the middle station;

[0035] S36, the middle station compares the returned result with the original mapping relationship table, and completes the nickname synchronization when the field contents are consistent.

[0036] Optionally, the S5 specifically includes:

[0037] S51, the industrial gateway traverses the user table and extracts the user identifier;

[0038] S52, the same device record is filtered in the device table according to the user identifier;

[0039] S53, the corresponding point record is found in the point table according to the device identifier, and the point name and data type are extracted;

[0040] S54, the user identifier, the device identifier, the point name and the data type are combined to form a collection task list;

[0041] S55, the industrial gateway sends a collection request instruction to the 4G communication terminal through the VPN link according to the collection task list.

[0042] Optionally, the S6 specifically includes:

[0043] S61, the 4G communication terminal collects the point value according to the device identifier and the point name contained in the collection task list;

[0044] S62, the 4G communication terminal compares the current point value with the last uploaded value;

[0045] S63, when the point is discrete and the current value is the same as the last value, the nickname is used as the identifier;

[0046] S64, when the point is non-discrete, or the current value is different from the last value, the point name is used as the identifier;

[0047] S65, the 4G communication terminal constructs a data message based on the identifier type, the point value and the timestamp.

[0048] Optionally, the S7 specifically includes:

[0049] S71, the industrial gateway receives the data message uploaded by the 4G communication terminal, and reads the user identifier field in the data message;

[0050] S72, the industrial gateway classifies data messages according to user identifiers, and establishes data cache queues corresponding to users respectively;

[0051] S73, the industrial gateway finds a record consistent with the user identifier in the user table, and extracts the user key field;

[0052] S74, the industrial gateway performs encryption operation on the data messages in each cache queue using the corresponding user key, and generates independent encrypted messages;

[0053] S75, the industrial gateway sends each encrypted message to the middle platform through the MQTT protocol according to the subject path matched with the user identifier.

[0054] Optionally, the S8 specifically comprises:

[0055] S81, the middle platform receives the data message uploaded through the MQTT protocol, and extracts the user identifier field in the data message;

[0056] S82, the middle platform finds a record consistent with the user identifier in the user table, and extracts the user key field;

[0057] S83, the middle platform decrypts the data message using the user key to obtain the plaintext content;

[0058] S84, the middle platform parses the identifier field in the plaintext content, and judges whether the identifier field is a nickname or a point name;

[0059] S85, when the identifier field is a nickname, the middle platform finds a mapping item matched with the nickname in the nickname mapping relationship table, and obtains the point name;

[0060] S86, the middle platform extracts the point value and the timestamp according to the identifier field or the restored point name, and constructs a point data record;

[0061] S87, the middle platform classifies the point data record according to the user identifier, and writes the point data record into a specified data table structure in the database.

[0062] Optionally, the S9 specifically comprises:

[0063] S91, the middle platform creates a user directory for a new user in the file system;

[0064] S92, the middle platform initializes the user table, the device table and the point table in the user directory, and writes the field structure and the table header information;

[0065] S93, the industrial gateway receives the access request of the new user, and creates a user directory consistent with the naming of the middle platform in the file system;

[0066] S94, the industrial gateway initializes the user table, the device table and the point table in the user directory, and the field structure is consistent with the middle station;

[0067] S95, the middle station and the industrial gateway perform configuration comparison operation, and verify the user directory structure, the table structure and the configuration information item by item, and complete the initialization data synchronization.

[0068] The beneficial effects of the application are:

[0069] In the existing industrial data acquisition system, the industrial gateway is usually deployed in the acquisition field, connected with the southward device through a wired mode, and the MQTT protocol and the Modbus protocol are used to complete the north-south communication. Although this mode has certain stability and maturity, since the industrial gateway generally has high computing performance, in the scene of only forwarding the acquisition data, the problem of idle resources and high construction cost is easily caused. In addition, in the case that multiple users share one industrial gateway, the traditional architecture only supports user isolation at the north interface, and the south data acquisition cannot be managed according to users, and there is a risk of mixed use of user data. At the same time, in the scene mainly with discrete points, the data update frequency is low, and continuous uploading of complete messages will cause waste of communication traffic.

[0070] In view of the above problems, the application provides an industrial data acquisition system based on VPDN for multi-user multiplexing and traffic saving. A virtual private network constructed by a 4G communication terminal accessing a VPDN protocol is used to realize the establishment of a remote data channel with an industrial gateway deployed centrally, instead of the traditional distributed gateway deployment mode, thereby significantly reducing the hardware cost. The system introduces a middle station point model and a nickname mapping mechanism, uses a hexadecimal nickname to represent a discrete point, reduces the length of the point field in the message, and effectively saves the upload traffic. The industrial gateway constructs a user table, a device table and a point table to structurally manage different user data, generates data messages according to users in the acquisition process and uploads them after encryption, and the middle station restores them according to the mapping relationship, so that the data is processed according to user isolation in the acquisition, transmission and analysis processes.

[0071] By constructing a virtual private channel, compressing message content and supporting a multi-user multiplexing mechanism in the south and north directions, the system improves the resource utilization rate, reduces the operation and maintenance cost, and solves the technical bottlenecks of the traditional data acquisition system in terms of high deployment cost, serious traffic waste and mixed use of user data. BRIEF DESCRIPTION OF DRAWINGS

[0072] The accompanying drawings are used to provide a further understanding of the application, and constitute a part of the specification, together with the embodiments of the application, to explain the application, and do not constitute a limitation on the application. In the drawings:

[0073] Figure 1Flow chart of industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving proposed by the present application;

[0074] Figure 2 System architecture diagram of industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving proposed by the present application;

[0075] Figure 3 Southbound channel connection diagram of industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving proposed by the present application;

[0076] Figure 4 Multi-user multiplexing mechanism structure diagram of industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving proposed by the present application;

[0077] Figure 5 Southbound device data acquisition flow chart of industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving proposed by the present application;

[0078] Figure 6 Northbound data upload flow chart of industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving proposed by the present application. DETAILED DESCRIPTION

[0079] The present application will now be further described in detail with reference to the drawings. These drawings are simplified schematic diagrams and only show the basic structure of the present application in a schematic manner, and thus only show the components related to the present application.

[0080] REFERENCE Figures 1-6 Industrial data acquisition system based on VPDN multi-user multiplexing and traffic saving, comprising:

[0081] A communication access module is configured to access a virtual private network based on a VPDN protocol through a 4G communication terminal, acquire a VPN address, and establish a southbound channel with an industrial gateway;

[0082] A point site model module is configured to establish a point site model by a middle station, generate a point site name, a data type, an initial value, and a discrete type identifier;

[0083] A flower name mapping module is configured to generate a flower name for a discrete type point site by a middle station, establish a mapping relationship, and synchronize to a 4G communication terminal;

[0084] A user structure module is configured to create a user table, a device table, and a point site table by an industrial gateway, and record a user identifier, a device identifier, and point site information;

[0085] An acquisition scheduling module is configured to traverse a user table by an industrial gateway, search a device table and a point site table, generate an acquisition task, and issue to a 4G communication terminal;

[0086] Data processing module, for 4G communication terminal to collect point data, judge the change, adopt the nickname or point name to construct the message;

[0087] Encryption upload module, for industrial gateway to receive and classify data message, encrypt according to user key, upload to the middle platform through MQTT protocol;

[0088] Decryption restoration module, for the middle platform to decrypt data message, restore point name and parse data content according to mapping relationship;

[0089] User initialization module, for when new user access, the middle platform and industrial gateway create user directory respectively, initialize structure and complete synchronization.

[0090] The application forms a complete industrial data acquisition system function link by constructing communication access, point model, nickname mapping, user structure, collection and scheduling, data processing, encryption upload, decryption restoration and user initialization function modules, realizes user isolation, flow saving, device unified management system level fusion design.

[0091] In the embodiment, the modules are realized by the following method:

[0092] S1, 4G communication terminal accesses virtual private network based on VPDN protocol, is in the same VPN network segment with industrial gateway, establishes southbound channel;

[0093] S2, the middle platform establishes point model, contains point name, data type, initial value and discrete type identification;

[0094] S3, the middle platform generates hexadecimal nickname for discrete type point, establishes point and nickname mapping relationship, issues to 4G communication terminal, returns confirmation information by 4G communication terminal, and the middle platform compares and synchronizes after consistency;

[0095] S4, industrial gateway creates user table, device table and point table, as user data structure;

[0096] S5, industrial gateway traverses user table, finds corresponding device table and point table, determines the southbound device and point of each user, and initiates collection request to 4G communication terminal;

[0097] S6, 4G communication terminal collects point value and judges the change, and the discrete type point with unchanged value is expressed by nickname, and other points retain point name, and generate data message;

[0098] S7, industrial gateway receives data message, classifies according to user, encrypts using user key, and uploads to the middle platform through MQTT protocol;

[0099] S8. The middle platform uses the user key to decrypt the message, restores the location name according to the mapping relationship, and completes the parsing and storage of user data.

[0100] S9. When a new user is added, the middleware and industrial gateway create user directories in their local paths, initialize the user table, device table and location table, and synchronize the configuration information.

[0101] This invention establishes a full-process control mechanism for industrial data acquisition based on a VPDN network environment by implementing functional connections between modules through a specific process, ensuring stability and hierarchical controllability throughout the entire process from southbound equipment acquisition to data reporting and parsing.

[0102] 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, 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.

[0103] This invention deploys the middleware platform and industrial gateway on the same hardware device, and completes instruction scheduling and data flow through bus communication. While ensuring functional isolation, it significantly improves the device integration and reduces hardware deployment costs and maintenance complexity.

[0104] In this embodiment, the user table records the user identifier, username, and user key; the device table records the device identifier, device name, VPN address, and port number; and the location table records the device identifier, location name, register address, data type, and description information.

[0105] This invention standardizes the data organization method under the user isolation mechanism by uniformly defining the field structure of the user table, equipment table, and location table, thereby improving the independence of user management, the security of data access, and the retrieval efficiency of the data structure.

[0106] In this embodiment, S3 specifically includes:

[0107] S31. The middle platform generates a name for the discrete points with a identifier of 1 in the point model. The name consists of 4 hexadecimal characters.

[0108] S32. The middle platform establishes a one-to-one correspondence between the point name and the flower name for each discrete point, forming a mapping table.

[0109] S33. The middleware will send the mapping relationship table to the 4G communication terminal;

[0110] The S34 and 4G communication terminals receive the mapping relationship table and complete the binding operation between the names and locations;

[0111] The binding results of the S35 and 4G communication terminals will be sent back to the central platform.

[0112] S36, the middle station compares the return result with the original mapping relationship table, and the field content is consistent to complete the nickname synchronization.

[0113] The application constructs a compact data representation for discrete points by a nickname generation and mapping relationship synchronization mechanism, and effectively avoids the collection misreporting caused by mapping errors by combining the nickname consistency confirmation process, thereby improving the reliability of discrete point data compression and identification.

[0114] In the embodiment, the S5 specifically includes:

[0115] S51, the industrial gateway traverses the user table to extract the user identifier;

[0116] S52, the same device record is screened in the device table according to the user identifier;

[0117] S53, the corresponding point record is found in the point table according to the device identifier, and the point name and data type are extracted;

[0118] S54, the user identifier, the device identifier, the point name and the data type are combined to form a collection task list;

[0119] S55, the industrial gateway sends a collection request instruction to the 4G communication terminal through the VPN link according to the collection task list.

[0120] The application clarifies the relationship between the device and the point bound by each user through the joint checking mechanism of the user table, the device table and the point table, realizes the accurate matching and scheduling generation of the data collection task in a multi-user environment, and enhances the scalability and scheduling control accuracy of the system.

[0121] In the embodiment, the S6 specifically includes:

[0122] S61, the 4G communication terminal collects the point value according to the device identifier and the point name contained in the collection task list;

[0123] S62, the 4G communication terminal compares the current point value with the last uploaded value;

[0124] S63, when the point is discrete and the current value is the same as the last value, the nickname is used as the identifier;

[0125] S64, when the point is non-discrete, or the current value is different from the last value, the point name is used as the identifier;

[0126] S65, the 4G communication terminal constructs a data message based on the identifier type, the point value and the timestamp.

[0127] The application realizes the message compression strategy based on the point change condition, reduces the message redundancy, and improves the resource utilization efficiency of data transmission by the selective use mechanism of the flower name and the point name, dynamically judging and switching the identification mode in the data acquisition process.

[0128] In the embodiment, the S7 specifically includes:

[0129] S71, the industrial gateway receives the data message uploaded by the 4G communication terminal, and reads the user identification field in the data message;

[0130] S72, the industrial gateway classifies the data message according to the user identification, and respectively establishes the data cache queue corresponding to the user;

[0131] S73, the industrial gateway finds the record consistent with the user identification in the user table, and extracts the user key field;

[0132] S74, the industrial gateway uses the corresponding user key to perform the encryption operation on the data message in each cache queue, and generates an independent encrypted message;

[0133] S75, the industrial gateway sends each encrypted message to the middle platform through the MQTT protocol according to the theme path matched with the user identification.

[0134] The application realizes the encryption isolation of the data uploading process by the uploading mechanism classified and encrypted by the user, and ensures the communication safety in the multi-user environment.

[0135] In the embodiment, the S8 specifically includes:

[0136] S81, the middle platform receives the data message uploaded by the MQTT protocol, and extracts the user identification field in the data message;

[0137] S82, the middle platform finds the record consistent with the user identification in the user table, and extracts the user key field;

[0138] S83, the middle platform calls the user key to decrypt the data message, and obtains the plaintext content;

[0139] S84, the middle platform parses the identification field in the plaintext content, and judges whether the identification field is the flower name or the point name;

[0140] S85, when the identification field is the flower name, the middle platform finds the mapping item matched with the flower name in the flower name mapping relationship table, and obtains the point name;

[0141] S86, the middle platform extracts the point value and the timestamp according to the identification field or the restored point name, and constructs the point data record;

[0142] S87, the middle station classifies the point data record according to the user identification, and writes into the specified data table structure in the database.

[0143] The application realizes complete restoration and classified storage of the uploaded data by the middle station through the processes of decrypting the message, restoring the alias and analyzing the point, constructs the analysis mechanism based on the dual attribution of the user and the point, and ensures the data consistency and classification accuracy.

[0144] In the embodiment, the S9 specifically includes:

[0145] S91, the middle station creates a user directory for the new user in the file system;

[0146] S92, the middle station initializes the user table, the device table and the point table in the user directory, and writes the field structure and the table header information;

[0147] S93, the industrial gateway receives the new user access request, and creates a user directory consistent with the middle station in the file system;

[0148] S94, the industrial gateway initializes the user table, the device table and the point table in the user directory, and the field structure is consistent with the middle station;

[0149] S95, the middle station and the industrial gateway perform configuration comparison operation, and verify the user directory structure, the table structure and the configuration information item by item, and complete the initialization data synchronization.

[0150] Through the double-end synchronization initialization mechanism of the middle station and the industrial gateway in the file system, the application realizes consistent deployment of the new user directory structure and the configuration information, guarantees the synchronization and the structural integrity of the new user access process, and supports the user dynamic expansion capability.

[0151] Example 1:

[0152] In order to verify the feasibility of the application in the implementation, the application is applied to the networking deployment of the industrial data acquisition system, the system accesses the VPDN private network through the 4G communication terminal, constructs the southbound communication channel, and centrally deploys the industrial gateway and the middle station function module on the server side, realizes the unified management and control and data acquisition of the southbound device, adopts the Internet of Things private network SIM card provided by the operator in the system deployment process, so that the 4G communication terminal automatically enters the preset VPN network segment after dialing, thereby realizing the IP direct connection-based communication with the industrial gateway, without laying physical wired channels.

[0153] On the server side, the middle platform establishes a point model and generates a hexadecimal name for a point with a discrete identifier, and a mapping relationship between the point and the name is generated, the middle platform sends the mapping relationship to the 4G communication terminal through the MQTT protocol, and after the communication terminal returns the confirmation information, the middle platform performs consistency comparison and completes synchronization after confirming the name matching.

[0154] The industrial gateway constructs a user data structure, creates a user table, a device table and a point table under a local path, the user table includes a user identifier, a user name and a user key, the device table includes a device identifier, a device name, a VPN address and a port number, and the point table includes a device identifier, a point name, a register address, a data type and description information, the gateway program determines the collection device and point configuration of each user by traversing the user table and searching the device table and the point table.

[0155] In the collection process, the 4G communication terminal processes the collected values according to the point table content, if the point is discrete and the value does not change, the original point name is replaced by the name to construct a message, if the point is not discrete or the value changes, the point name is retained, the industrial gateway receives the data message, classifies according to the user identifier, and uploads to the middle platform through the MQTT protocol after encryption using the user key.

[0156] After receiving the encrypted message, the middle platform decrypts the data using the corresponding user key, restores the point name according to the name mapping relationship, and stores the data in the user data table after parsing, realizing effective isolation and management of the collected data, in the whole process, the industrial gateway and the middle platform are deployed on the same hardware device, and communicate through the local loopback address, reducing the deployment cost and system complexity.

[0157] Under the multi-user multiplexing mechanism, when a new user accesses, the middle platform and the industrial gateway create a user directory under the local path, and initialize the user table, the device table and the point table, the gateway program executes the data collection and classification upload process in the user dimension, all data are independently encrypted and classified in the user dimension between the gateway and the middle platform, ensuring data information isolation and preventing data mixing, meeting the industrial data security requirements.

[0158] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A VPDN based multi-user multiplexing and traffic conserving industrial data acquisition system, characterized in that, The application comprises the following steps: A communication access module is used to access a virtual private network based on a VPDN protocol through a 4G communication terminal, obtain a VPN address, and establish a southbound channel with an industrial gateway; A point site model module is used to establish a point site model by a middle station, generate a point site name, a data type, an initial value, and a discrete type identifier; A flower name mapping module is used to generate a flower name for a discrete type point site by a middle station, establish a mapping relationship, and synchronize to a 4G communication terminal, specifically comprising the following steps: The middle station generates a flower name for a point site with a discrete type identifier of 1 in the point site model, and the flower name is composed of 4 hexadecimal characters; The middle station establishes a one-to-one correspondence between a point site name and a flower name for each discrete type point site, and forms a mapping relationship table; The middle station issues the mapping relationship table to the 4G communication terminal; The 4G communication terminal receives the mapping relationship table and completes the binding operation of the flower name and the point site; The 4G communication terminal returns the binding result to the middle station; The middle station compares the returned result with the original mapping relationship table, and completes the flower name synchronization when the field contents are consistent; A user structure module is used to create a user table, a device table, and a point site table by an industrial gateway, and record a user identifier, a device identifier, and point site information; A collection and scheduling module is used to traverse the user table by the industrial gateway, find the device table and the point site table, generate a collection task, and issue it to the 4G communication terminal; A data processing module is used to collect point site data by the 4G communication terminal, judge the change, and construct a message by using a flower name or a point site name, specifically comprising the following steps: The 4G communication terminal collects point site values according to the device identifier and the point site name contained in the collection task list; The 4G communication terminal compares the current point site value with the last uploaded value; When the point site is discrete and the current value is the same as the last value, the flower name is used as the identifier; When the point site is non-discrete, or the current value is different from the last value, the point site name is used as the identifier; The 4G communication terminal constructs a data message based on the identifier type, the point site value, and the time stamp; An encryption and uploading module is used to receive and classify data messages by the industrial gateway, encrypt according to a user key, upload to the middle station through an MQTT protocol; A decryption and restoration module is used to decrypt data messages by the middle station, restore the point site name according to the mapping relationship, and analyze the data content; A user initialization module is used to create a user directory by the middle station and the industrial gateway respectively when a new user accesses, initialize the structure, and complete the synchronization.

2. The VPDN-based multi-user multiplexing and traffic conserving industrial data acquisition system of claim 1, wherein, The modules are realized through the following methods: S1, the 4G communication terminal accesses a virtual private network based on a VPDN protocol, is in the same VPN network segment with the industrial gateway, and establishes a southbound channel; S2, the middle station establishes a point site model, which contains a point site name, a data type, an initial value, and a discrete type identifier; S3, the middle station generates a hexadecimal flower name for a discrete type point site, establishes a mapping relationship between the point site and the flower name, issues it to the 4G communication terminal, returns confirmation information by the 4G communication terminal, and completes the synchronization after the middle station compares and confirms consistency; S4, the industrial gateway creates a user table, a device table, and a point site table, which are used as a user data structure; S5, the industrial gateway traverses the user table, finds the corresponding device table and point site table, determines the southbound device and point site of each user, and initiates a collection request to the 4G communication terminal; S6, the 4G communication terminal collects point value and judges the change, the discrete point with unchanged value is represented by the name, and other point names are reserved to generate data messages; S7, the industrial gateway receives the data message, classifies the user, encrypts the data message using the user key, and uploads the data message to the middle platform through the MQTT protocol; S8, the middle platform decrypts the message using the user key, restores the point name according to the mapping relationship, and completes the user data analysis and storage; S9, when a new user accesses, the middle platform and the industrial gateway create a user directory under the local path, initialize the user table, the device table and the point table, and synchronize the configuration information.

3. The VPDN-based multi-user multiplexing and traffic conserving industrial data acquisition system of claim 2, wherein, The middle platform is a server-side control platform in the system, responsible for unified management of point model configuration, name synchronization, user information initialization, data analysis and storage, the industrial gateway and the middle platform are deployed on the same hardware device, and the task division and data interaction are completed through internal bus or local loop address communication.

4. The VPDN-based multi-user multiplexing and traffic conserving industrial data acquisition system of claim 2, wherein, The user table records the user identifier, the user name and the user key, the device table records the device identifier, the device name, the VPN address and the port number, and the point table records the device identifier, the point name, the register address, the data type and the description information.

5. The VPDN-based multi-user multiplexing and traffic conserving industrial data acquisition system of claim 2, wherein, The S5 specifically comprises: S51, the industrial gateway traverses the user table and extracts the user identifier; S52, according to the user identifier, the same device record is screened in the device table according to the device identifier; S53, according to the device identifier, the corresponding point record is found in the point table, and the point name and the data type are extracted; S54, the user identifier, the device identifier, the point name and the data type are combined to form a collection task list; S55, the industrial gateway sends a collection request instruction to the 4G communication terminal through the VPN link according to the collection task list.

6. The VPDN-based multi-user multiplexing and traffic conserving industrial data acquisition system of claim 2, wherein, The S7 specifically comprises: S71, the industrial gateway receives the data message uploaded by the 4G communication terminal, and reads the user identifier field in the data message; S72, the industrial gateway classifies the data message according to the user identifier, and establishes a data cache queue corresponding to the user; S73, the industrial gateway finds the record consistent with the user identifier in the user table, and extracts the user key field; S74, the industrial gateway uses the corresponding user key to perform encryption operation on the data message in each cache queue to generate independent encrypted message; S75, the industrial gateway sends each encrypted message to the middle platform through the MQTT protocol according to the topic path matched with the user identifier.

7. The VPDN-based multi-user multiplexing and traffic conserving industrial data acquisition system of claim 2, wherein, The S8 specifically comprises: S81, the middle platform receives the data message uploaded through the MQTT protocol, and extracts the user identifier field in the data message; S82, the middle platform finds the record consistent with the user identifier in the user table, and extracts the user key field; S83, the middle platform calls the user key to decrypt the data message to obtain the plaintext content; S84, the middle platform analyzes the identifier field in the plaintext content, and judges whether the identifier field is the name or the point name; S85, when the identifier field is the name, the middle platform finds the mapping item matched with the name in the name mapping relationship table to obtain the point name; S86, the middle platform extracts the point value and the timestamp according to the identifier field or the restored point name, and constructs the point data record; S87, the middle station classifies the point data records according to the user identification and writes into the specified data table structure in the database.

8. The VPDN-based multi-user multiplexing and traffic conserving industrial data acquisition system of claim 2, wherein, The S9 specifically includes: S91, the middle station creates a user directory for the new user in the file system; S92, the middle station initializes the user table, the device table and the point table in the user directory, writes the field structure and the table header information; S93, the industrial gateway receives the access request of the new user, creates a user directory consistent with the middle station in the file system; S94, the industrial gateway initializes the user table, the device table and the point table in the user directory, and the field structure is consistent with the middle station; S95, the middle station and the industrial gateway perform configuration comparison operation, and verify the user directory structure, the table structure and the configuration information item by item, and complete the initialization data synchronization.

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