A GPRS-based frequency converter bidirectional communication module card and a data transmission control method thereof

Abstract

This invention discloses a GPRS-based bidirectional communication module card for frequency converters and its data transmission control method, belonging to the field of industrial Internet of Things (IoT) communication technology. It aims to solve the problems of easy loss of critical data, low utilization of storage resources, and low retransmission efficiency caused by fluctuations in GPRS network link quality in existing frequency converter wireless monitoring. The module card includes a microprocessor unit, a Modbus interface unit, a GPRS communication unit, a data storage unit, and a power management unit. The microprocessor unit monitors network link quality parameters in real time. The Flash persistent storage area of ​​the data storage unit is divided into high-priority partitions and regular partitions for hierarchical storage of data packets that failed to upload. The method of this invention includes a data upload process and a control command issuance process. Through network status detection, hierarchical storage, adaptive retransmission, and security authentication mechanisms, it achieves complete preservation of critical data, efficient utilization of storage resources, and secure and reliable remote control in complex network environments.

Description

Technical Field

[0001] This invention belongs to the field of industrial Internet of Things communication technology, specifically relating to a GPRS-based bidirectional communication module card for frequency converters and its data transmission control method. Background Technology

[0002] As a core device in industrial drive control, frequency converters (VDCs) regulate the speed of asynchronous motors by changing the power supply frequency and are widely used in applications such as water pumps, fans, conveyor belts, and production lines. With the promotion of Industrial Internet of Things (IIoT) applications, remote centralized monitoring of VDCs located in geographically dispersed areas or where on-site wiring is difficult has become an important requirement for reducing maintenance costs and improving equipment manageability. Traditional solutions mainly use RS485 bus or Ethernet wired connections to connect VDCs to the monitoring system. However, in scenarios where equipment is widely distributed, its location frequently changes, or construction conditions are limited, wired methods suffer from high wiring costs, long construction periods, and difficulties in expansion.

[0003] To overcome the limitations of wired communication, existing technologies have developed modules or systems that convert inverter Modbus communication into GPRS wireless transmission. For example, Chinese patent publication number CN201497908U discloses a wireless intelligent remote monitoring and maintenance system for inverters, which uses a data transmission module to convert wired signals to wireless networks and access the Internet. However, in actual industrial settings, GPRS networks often experience brief or prolonged interruptions due to electromagnetic interference, base station switching, or weak signal coverage. Most existing solutions either discard unsent data packets or perform only a limited number of immediate retries when the network is interrupted, resulting in the loss of critical operational status and fault information. A few modules have data caching capabilities, but they typically store all data indiscriminately, without differentiating based on data importance or dynamically adjusting data acquisition frequency, retry strategies, storage allocation, or retransmission order according to changes in network link quality. This leads to storage space being occupied by large amounts of routine periodic data during prolonged network interruptions, while high-priority fault alarm data is overwritten. Furthermore, retransmissions after network recovery often employ unoptimized full retransmission, increasing unnecessary bandwidth consumption and easily causing discrepancies between the data arrival order and the actual generation order. Therefore, a new technical solution is needed to address the problems of critical data loss, low storage resource utilization, low retransmission efficiency, and susceptibility to out-of-order delivery caused by fluctuations in GPRS network link quality. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a GPRS-based bidirectional communication module card for frequency converters and its data transmission control method, so as to solve the problems of easy loss of key data, low utilization of storage resources, low retransmission efficiency and easy out-of-order transmission caused by fluctuations in the quality of GPRS network links in existing frequency converter wireless monitoring.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a GPRS-based bidirectional communication module card for frequency converters, comprising a microprocessor unit, a Modbus interface unit, a GPRS communication unit, a data storage unit, and a power management unit.

[0006] The microprocessor unit integrates a hardware CRC check module and a hardware encryption module for performing data protocol conversion, data encryption / decryption, network link quality parameter monitoring, and adaptive data storage and retransmission control based on the network link quality parameters. The Modbus interface unit connects to the inverter's Modbus communication port, receiving operating data output by the inverter and sending control commands to the inverter. The GPRS communication unit establishes a connection with the GPRS mobile network, sends data packets to be transmitted to the remote monitoring terminal, receives control commands from the remote monitoring terminal, and provides the microprocessor unit with the current network link quality parameters. The data storage unit includes a RAM temporary buffer, an EEPROM configuration storage area, and a Flash persistent storage area. The Flash persistent storage area is divided into high-priority and regular partitions for hierarchical storage of data packets that failed to upload, based on data type and the network link quality parameters. The power management unit connects to the inverter's power supply system, providing a stable operating voltage to each unit.

[0007] Furthermore, the microprocessor unit incorporates a network state machine, which includes online, offline, and recovery states. In the offline state, the microprocessor unit directs the data to be transmitted to the corresponding partition of the Flash persistent storage area. When switching to the recovery state, a retransmission thread is initiated based on the current network link quality parameters. Following timestamp order and a priority weighting rule positively correlated with the network link quality parameters, the unsuccessfully uploaded data stored in the Flash persistent storage area is read and uploaded. The better the network link quality parameters, the shorter the retransmission interval for high-priority partition data.

[0008] Furthermore, the Modbus interface unit supports Modbus RTU, Modbus ASCII, and Modbus TCP protocols, and protocol switching is achieved through hardware DIP switches or software configuration. The baud rate supports adaptive matching with the inverter communication parameters.

[0009] Secondly, the present invention also provides a data transmission control method based on the above-mentioned communication module card, including a data upload process. The data upload process includes: S100. The Modbus interface unit collects operating data from the frequency converter according to a preset reading cycle. The operating data includes regular periodic data and abnormal event data.

[0010] S200: The microprocessor unit performs protocol parsing and format conversion on the collected running data to generate a data packet to be transmitted containing a data type identifier.

[0011] S300: The microprocessor unit detects the network connection status of the GPRS communication unit and the network link quality parameters. When the network connection is normal, it sends the data packet to be transmitted to the remote monitoring terminal in real time, and after receiving the confirmation response, it marks it as sent and releases the corresponding storage space in the RAM temporary buffer.

[0012] S400. When the network connection is abnormal or the transmission fails, the data packet to be transmitted, along with the timestamp and the failure reason code, is written to the corresponding partition of the Flash persistent storage area according to the data type and the network link quality parameters at that time.

[0013] S500. When the GPRS communication unit is detected to have restored the network connection, the microprocessor unit reads the data that was not successfully uploaded from the Flash persistent storage area according to the current network link quality parameters and performs retransmission in the order of timestamps. After each data is successfully retransmitted and an acknowledgment is received, the corresponding record is deleted from the Flash persistent storage area.

[0014] Further, in step S300, detecting the network connection status and the network link quality parameters specifically includes: the microprocessor unit queries the GPRS communication unit for network registration status, socket connection status, and received signal strength indication value via AT commands. If N consecutive queries show that the link is disconnected or not registered, the network connection is determined to be abnormal, where N is a preset integer greater than or equal to 2. When the network link quality parameter is lower than a first preset threshold, the upload attempt interval for high-priority data is shortened and its maximum retry count is increased.

[0015] Further, in step S100, when the Modbus interface unit detects a fault code returned by the frequency converter, it triggers a hardware interrupt to the microprocessor unit. In response to the interrupt, the microprocessor unit suspends its regular periodic read tasks and prioritizes the execution of the abnormal event data acquisition and uploading process for the fault code.

[0016] Further, the hierarchical storage in step S400 specifically includes: judging based on the data type identifier of the data packet to be transmitted; if it is a fault code or alarm data, it is written to the high-priority partition of the Flash persistent storage area and a timestamp is recorded; if it is regular periodic data, it is written to the regular partition. When the remaining space in the regular partition is insufficient, the oldest data is overwritten according to the first-in-first-out rule. When the network link quality parameter is lower than a second preset threshold, the microprocessor unit first performs lossless differential encoding compression on the regular periodic data before writing it to the regular partition.

[0017] Furthermore, the method also includes a control command issuance process, which includes: T100, the GPRS communication unit receives an encrypted control command sent by the remote monitoring terminal, the encrypted control command including terminal authentication information and command content.

[0018] T200: The microprocessor unit decrypts the encryption control instruction and verifies the legality of the terminal authentication information; if the verification fails, it refuses to execute and records the abnormal access log.

[0019] After T300 verification is successful, the decrypted instruction content is converted into a Modbus protocol write instruction frame and sent to the frequency converter through the Modbus interface unit.

[0020] T400: The microprocessor unit reads the execution feedback result of the frequency converter through the Modbus interface unit, and transmits the execution result back to the remote monitoring terminal through the GPRS communication unit.

[0021] Furthermore, in step T200, the terminal authentication information includes a terminal identifier, a timestamp, and a message authentication code based on a shared key. The microprocessor unit uses the built-in hardware encryption module to quickly verify the message authentication code.

[0022] Furthermore, the method also includes a remote parameter configuration process: the microprocessor unit receives configuration parameters sent by the remote monitoring terminal through the GPRS communication unit. These configuration parameters include Modbus baud rate, protocol type, data read cycle, server IP address, and port number. The microprocessor unit writes the received configuration parameters into the EEPROM configuration storage area and loads and applies them upon the next power-on.

[0023] This invention discloses a GPRS-based bidirectional communication module card for frequency converters and its data transmission control method. Its core lies in achieving bidirectional wireless communication between the frequency converter and a remote monitoring terminal through modular design. Furthermore, it addresses the issue of GPRS network link quality fluctuations by designing hierarchical storage, adaptive retransmission, and dynamic adjustment strategies. Specifically, compared to existing technologies, this invention has the following significant advantages: The module card adopts a modular architecture consisting of a microprocessor unit, a Modbus interface unit, a GPRS communication unit, a data storage unit, and a power management unit. The units work together to ensure reliable connection with the frequency converter and stable wireless communication with remote terminals. No on-site wiring is required, which effectively reduces deployment costs and construction time, and is suitable for geographically dispersed scenarios where wiring is difficult.

[0024] The data storage unit innovatively divides the Flash persistent storage area into high-priority partitions and regular partitions. During network outages, the system performs hierarchical storage based on data type identifiers: high-priority information such as fault codes is written to the high-priority partition and timestamped, while regular periodic data is stored in the regular partition. When the regular partition runs out of space, the oldest data is overwritten according to a first-in, first-out (FIFO) rule. Furthermore, when network link quality falls below a threshold, regular data is losslessly differentially encoded and compressed before being written back. This mechanism achieves physical isolation between critical data and regular data, fundamentally preventing the loss of high-priority fault data due to overwriting by regular data, ensuring the integrity and traceability of fault information.

[0025] At the data transmission control level, the microprocessor unit monitors network link quality parameters (such as signal strength and registration status) in real time and implements end-to-end adaptive control based on these parameters. When the network is abnormal, it automatically switches to tiered storage; after network recovery, a retransmission thread is initiated based on the current network quality, retransmitting data according to timestamp order and a priority weighting rule positively correlated with network quality. The better the network quality, the shorter the retransmission interval for high-priority data. When the network quality falls below a first preset threshold, the interval between high-priority data upload attempts is shortened and the number of retries is increased, creating more opportunities for fault information to be transmitted. This adaptive control improves retransmission efficiency, avoids the waste of traffic and congestion caused by full retransmission during network recovery, and ensures the consistency of data order.

[0026] In terms of protocol adaptation and security, the Modbus interface unit supports multiple protocols and adaptive baud rate matching, significantly improving the module card's compatibility and enabling seamless adaptation to different inverter models. The control command issuance process incorporates encryption and authentication mechanisms. Commands include terminal identifiers, timestamps, and message authentication codes based on shared keys. The microprocessor unit utilizes a built-in hardware encryption module for rapid decryption and verification, effectively resisting replay attacks and forged commands, ensuring that only legitimate terminals can execute sensitive operations. Simultaneously, the remote parameter configuration function allows key parameters to be dynamically adjusted and written to EEPROM via a remote terminal, eliminating the need for on-site operation and significantly reducing the maintenance costs of distributed equipment.

[0027] Furthermore, this invention prioritizes the processing of fault codes returned by the frequency converter through a hardware interrupt mechanism. When a fault is detected, an interrupt is triggered immediately, the regular reading task is paused, and the fault data processing flow is executed first. This ensures that the fault information breaks through the software polling cycle limit and is reported or stored in a high-priority partition as soon as possible, thereby minimizing the fault response time and improving the real-time alarm capability of the industrial monitoring system. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a structural block diagram of a GPRS-based bidirectional communication module card for frequency converters provided in an embodiment of the present invention.

[0030] Figure 2 This is a flowchart of the data upload process in the data transmission control method provided in an embodiment of the present invention.

[0031] Figure 3 A flowchart of the data upload process provided in this embodiment of the invention.

[0032] Figure 4 This is a flowchart of the control command issuance process in the data transmission control method provided in the embodiments of the present invention.

[0033] Figure 5 A flowchart illustrating the control command issuance process provided in an embodiment of the present invention.

[0034] The following are the markings in the attached diagram: 100 Microprocessor unit; 200 Modbus interface unit; 300 GPRS communication unit; 400 Power management unit; 500 Data storage unit; 510 RAM temporary buffer area; 520 EEPROM configuration storage area; 530 Flash persistent storage area. Detailed Implementation

[0035] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0036] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] In traditional industrial frequency converter remote monitoring systems, fluctuations in GPRS network link quality can easily lead to the loss of critical operating status and fault information during transmission. This results in low storage resource utilization, inefficient data retransmission, and data arrival order discrepancies. Specifically, when a network outage occurs, existing solutions fail to differentiate data processing based on its importance. Regular periodic data and high-priority fault alarm data are indiscriminately cached in storage units, causing storage space to be occupied by a large amount of regular data while high-priority data is overwritten due to insufficient space. Furthermore, the retransmission operation after network recovery lacks strategy optimization, employing a full retransmission mechanism without order adjustment. This leads to a discrepancy between the arrival order of data packets and their actual generation order, affecting the real-time response capability and data integrity of the monitoring system.

[0038] In response, this application proposes a GPRS-based bidirectional communication module card for frequency converters, such as... Figure 1 As shown, it includes: The microprocessor unit 100 has a built-in hardware CRC check module and hardware encryption module, which are used to perform data protocol conversion, data encryption and decryption, network link quality parameter monitoring, and adaptive data storage and retransmission control based on network link quality parameters. Modbus interface unit 200 is connected to the Modbus communication port of the frequency converter and is used to receive the operating data output by the frequency converter and send control commands to the frequency converter. The GPRS communication unit 300 is used to establish a connection with the GPRS mobile network, send the data packets to be transmitted to the remote monitoring terminal, receive control commands issued by the remote monitoring terminal, and provide the current network link quality parameters to the microprocessor unit 100. The data storage unit 500 includes a RAM temporary buffer 510, an EEPROM configuration storage area 520, and a Flash persistent storage area 530. The Flash persistent storage area 530 is divided into a high-priority partition and a regular partition, which are used to hierarchically store data packets that failed to be uploaded according to data type and network link quality parameters. The power management unit 400 is connected to the power supply system of the frequency converter and is used to provide a stable operating voltage to each unit.

[0039] The microprocessor unit 100 incorporates a hardware CRC check module and a hardware encryption module, used for data protocol conversion, data encryption and decryption, network link quality parameter monitoring, and adaptive data storage and retransmission control based on network link quality parameters. In practical applications, adaptive data storage and retransmission control based on network link quality parameters refers to the process of dynamically adjusting data processing strategies according to real-time network conditions. This can be achieved by monitoring parameters such as network registration status, signal strength, or bit error rate, for example, by periodically querying the status information of the GPRS communication unit. Its main purpose is to optimize data storage and retransmission behavior when network quality fluctuates, thereby avoiding the loss of critical data. Furthermore, the data storage unit 500 includes a RAM temporary cache area 510, an EEPROM configuration storage area 520, and a Flash persistent storage area 530. The Flash persistent storage area 530 is divided into a high-priority partition and a regular partition for hierarchical storage of data packets that failed to be uploaded, based on data type and network link quality parameters. Specifically, the hierarchical storage of the Flash persistent storage area 530 can be understood as managing the storage space in layers according to data importance. It can use data identifiers or content analysis to determine the data type. For example, fault alarm data is assigned to the high-priority partition. This is mainly to prioritize the integrity of critical data when storage resources are limited. Therefore, this embodiment uses network link quality parameters as a real-time decision-making basis throughout the entire process of data storage and retransmission, achieving dynamic adaptability and resource optimization in data processing. Specifically, the microprocessor unit 100 performs adaptive control based on the monitoring results of the network link quality parameters. Combined with the hierarchical storage mechanism of the data storage unit 500, it ensures that critical data is prioritized and not overwritten during network interruptions, and is retransmitted in an orderly manner according to priority when the network recovers. This effectively solves the problems of data loss, wasted storage space, and disordered retransmission caused by network fluctuations in the background technology. Specifically, the GPRS communication unit 300 is used to establish a connection with the GPRS mobile network and provide network link quality parameters. It can use a standard AT command set or a dedicated interface protocol to implement parameter feedback. Simultaneously, the Modbus interface unit 200 connects to the Modbus communication port of the inverter for data exchange. It can use electrical isolation circuits or optocouplers to enhance anti-interference capabilities. The power management unit 400 connects to the power supply system of the inverter to provide stable voltage. It can use a wide voltage input design or filtering circuit to adapt to power supply fluctuations in industrial environments. As a preferred implementation, the monitoring of network link quality parameters can be extended to base station handover status or data packet retransmission rate. The hierarchical storage strategy can dynamically adjust the partition capacity allocation in combination with network quality parameters, thereby significantly improving the reliability of data transmission and resource utilization efficiency while ensuring the basic functions of the system.

[0040] In industrial IoT applications, this inverter bidirectional communication module card achieves reliable and adaptable data transmission through the collaborative operation of hardware modules. The microprocessor unit 100 continuously receives network link quality parameters from the GPRS communication unit 300, including signal strength indicators and socket connection status, for dynamic adjustment of the data processing flow. When the network connection is normal, the operating data collected by the Modbus interface unit 200 from the inverter is converted to a protocol and transmitted in real time to the remote monitoring terminal. Simultaneously, the GPRS communication unit 300 forwards the received control commands to the microprocessor unit 100 for decryption. If a network interruption is detected, the data packets that were not successfully uploaded are categorized and directed to the data storage unit 500 according to their data type identifier and the network link quality parameters at the time. Fault alarm data is stored in the high-priority partition of the Flash persistent storage area 530, while regular periodic data is written to the regular partition. The power management unit 400 ensures that all components maintain a stable voltage supply under inverter power fluctuations. Furthermore, once the network is restored, the microprocessor unit 100 initiates a retransmission mechanism based on real-time network link quality parameters, prioritizing the reading of data from high-priority partitions and executing the upload in timestamp order. For data from regular partitions, the retransmission interval is dynamically adjusted based on network quality, thereby avoiding invalid retries and ensuring data timing consistency.

[0041] Therefore, this technical solution effectively avoids the risk of losing critical operational status information during network fluctuations through a decision-making mechanism that links network link quality parameters with data types; the hierarchical storage strategy significantly improves the utilization efficiency of storage resources and prevents high-priority data from being overwritten by regular data; the retransmission process dynamically optimizes priority and interval based on network quality, reducing the probability of data misordering and reducing unnecessary traffic consumption, thereby ensuring the reliability and real-time performance of data transmission in complex electromagnetic environments for industrial monitoring systems.

[0042] This application further proposes a built-in network state machine in the microprocessor unit 100, which includes an online state, an offline state, and a recovery state. When in the offline state, the microprocessor unit 100 directs the data to be transmitted to the corresponding partition of the Flash persistent storage area 530. When switching to the recovery state, a retransmission thread is started according to the network link quality parameters at that time, and the unsuccessfully uploaded data stored in the Flash persistent storage area 530 is read and uploaded according to the timestamp order and the priority weighting rule positively correlated with the network link quality parameters. The better the network link quality parameters, the shorter the retransmission interval of the high-priority partition data.

[0043] Among them, the network state machine refers to the state management system implemented inside the microprocessor unit 100, which is used to accurately identify the real-time stage of the network connection. It can be implemented using a finite state machine algorithm or a state transition table, with the aim of providing clear state basis for data processing logic. The data-oriented storage area refers to the mechanism of dynamically allocating storage locations according to data type and network link quality parameters. It can be implemented using a partition mapping table or a storage strategy configuration file, with the aim of ensuring that high-priority information such as fault codes or alarm data is stored in high-priority partitions first. The retransmission thread startup refers to the mechanism of dynamically triggering data retransmission operations based on real-time link quality. It can be implemented using timer triggering or event-driven methods, with the aim of avoiding blind full retransmission when the network has just recovered. The timestamp order and priority weighting rule refers to the strategy of ensuring that the data timing is consistent with the actual generation order and dynamically adjusting the retransmission priority during the data retransmission process. It can be implemented using a priority queue or a weighted round-robin algorithm. The relationship between the retransmission interval and network link quality parameters refers to the dynamic correlation mechanism between network link quality parameters and the frequency of high-priority data retransmission. It can be implemented using a linear mapping function or segmented threshold control, with the aim of making full use of high-quality link resources to prioritize the transmission of critical data.

[0044] Specifically, the network state machine continuously monitors the network registration status and socket connection status of the GPRS communication unit 300. When multiple consecutive link disconnections are detected, it automatically switches to the offline state. At this time, the microprocessor unit 100 directs the data to be transmitted to the high-priority partition or regular partition of the Flash persistent storage area 530 according to the data type identifier. When the network is restored, the state machine switches to the recovery state, and the microprocessor unit 100 starts the retransmission thread according to the received signal strength indicator value. First, it reads the high-priority partition data in the order of timestamps. It dynamically adjusts the retransmission interval according to the network link quality parameters. When the link quality is good, the high-priority data retransmission interval is shortened to quickly transmit key information. When the link quality is poor, the interval is appropriately extended to avoid congestion. At the same time, regular data is gradually uploaded to ensure data timing consistency and optimize storage space utilization.

[0045] As a preferred embodiment, the solution of this application is implemented as follows: The microprocessor unit 100 can be a microcontroller with an ARM Cortex-M4 core, and its built-in network state machine realizes state switching by polling the network registration status of the GPRS communication unit 300; when in offline state, fault alarm data is directed to the high-priority partition of the Flash persistent storage area 530, and regular periodic data is directed to the regular partition; when switching to recovery state, a retransmission thread is started according to the received signal strength indication value provided by the GPRS communication unit 300. When the signal strength is at a good level, the retransmission interval of the high-priority partition data is set to a shorter time, and the retransmission interval of the regular partition data is set to a longer time; when the signal strength is at a medium level, the retransmission interval of the high-priority partition data is appropriately extended, and the retransmission interval of the regular partition data is further extended; the retransmission process is strictly executed according to the timestamp order to ensure that the data arrival order is consistent with the actual generation order.

[0046] Through the above solution, this application effectively solves the reliability problem of data processing under network fluctuation environment, prevents the loss of key operating status and fault information, avoids the storage space being occupied by regular periodic data and thus causing high priority fault alarm data to be overwritten, and optimizes the retransmission order after network recovery, reduces unnecessary traffic consumption, and ensures the consistency between the data arrival order and the actual generation order.

[0047] This application further proposes that the Modbus interface unit 200 supports Modbus RTU, Modbus ASCII and Modbus TCP protocols, and realizes protocol switching through hardware DIP switches or software configuration. The baud rate supports adaptive matching with the inverter communication parameters.

[0048] In practical applications, support for Modbus RTU, Modbus ASCII, and Modbus TCP protocols means that the Modbus interface unit 200 has the ability to parse and generate data frames for these three protocols. This can be achieved using a multi-protocol parsing engine in conjunction with a reconfigurable communication controller. Specifically, the frame format rules of the corresponding protocol can be dynamically loaded through the configuration register. Hardware DIP switches refer to mechanical switch arrays installed on the physical casing of the communication module card. These can be implemented using DIP switches or rotary encoder switches, and their purpose is to provide a physical-level configuration channel without software intervention. Software configuration refers to setting protocol parameters through configuration commands issued by a remote monitoring terminal. This can be achieved using custom function codes or dedicated configuration messages based on Modbus protocol extensions, and its purpose is to achieve contactless remote adaptation. Baud rate adaptive matching refers to the process of automatically detecting the communication rate characteristics at the inverter end and adjusting the operating parameters of the interface unit. This can be achieved using a signal edge detection circuit in conjunction with a dynamic clock divider, and its purpose is to eliminate the risk of errors in manual configuration.

[0049] Specifically, the Modbus interface unit 200 analyzes the signal characteristics on the communication line in real time through its built-in protocol identification module. When the inverter's power-on initialization signal is detected, it automatically triggers the protocol type determination process: if a serial frame structure of start bit-data bit-parity bit-stop bit is identified, it is determined to be Modbus RTU or ASCII protocol; if Ethernet frame header characteristics are detected, it is determined to be Modbus TCP protocol. The state of the hardware DIP switch is periodically scanned by the microprocessor unit 100. When a change in switch position is detected, the protocol configuration register is updated immediately. The software configuration command is received through the GPRS communication unit 300, decrypted and verified for legality by the microprocessor unit 100, and then written to the EEPROM configuration storage area 520. The baud rate adaptive matching mechanism calculates the actual communication rate by monitoring the time interval of the first valid data frame sent by the inverter, and dynamically adjusts the clock division coefficient of the interface unit 200 to ensure that the sampling point falls precisely at the center position of the data bit. These features work together to enable the interface unit 200 to be deployed in the face of heterogeneous frequency converter devices with plug-and-play capability, fundamentally reducing the failure points in the protocol adaptation process.

[0050] As a specific implementation method, the solution of this application is implemented as follows: When the communication module card is installed on a cement plant production line, the Modbus interface unit 200 is preset to Modbus RTU mode via a hardware DIP switch to adapt to the ABB frequency converter; when the equipment is moved to a new workshop and needs to be connected to a Siemens frequency converter, the on-site engineer switches the protocol to Modbus ASCII by toggling the DIP switch, and the interface unit 200 immediately detects the ASCII character frame returned by the frequency converter, automatically completes baud rate matching and establishes a communication link; in the remote commissioning scenario, the monitoring center updates the protocol type to Modbus TCP through software configuration instructions, the microprocessor unit 100 writes the configuration parameters into the EEPROM configuration storage area 520, and after restarting, the Modbus interface unit 200 establishes a TCP connection via the Ethernet interface to realize networked monitoring of the Schneider frequency converter.

[0051] In another embodiment, this application also discloses a data transmission control method based on the aforementioned communication module card, including a data upload process, such as... Figure 2 and Figure 3 As shown, the data upload process specifically includes the following steps: S100: The Modbus interface unit 200 collects operating data from the frequency converter according to a preset reading cycle. The operating data includes regular periodic data and abnormal event data. S200: The microprocessor unit 100 performs protocol parsing and format conversion on the collected running data to generate a data packet to be transmitted containing data type identifiers. S300 and microprocessor unit 100 detect the network connection status and network link quality parameters of GPRS communication unit 300. When the network connection is normal, the data packet to be transmitted is sent to the remote monitoring terminal in real time. After receiving the confirmation response, it is marked as sent and the corresponding storage space in RAM temporary buffer 510 is released. S400. When the network connection is abnormal or the transmission fails, the data packet to be transmitted, along with the timestamp and failure reason code, is written to the corresponding partition of the Flash persistent storage area 530 according to the data type and the network link quality parameters at that time. S500: When the GPRS communication unit 300 is detected to have restored the network connection, the microprocessor unit 100 reads the data that was not successfully uploaded from the Flash persistent storage area 530 in the order of timestamps according to the current network link quality parameters and performs retransmission. After each data is successfully retransmitted and an acknowledgment is received, the corresponding record is deleted from the Flash persistent storage area 530.

[0052] The core innovation of this embodiment lies in the dynamic integration of data type identifiers and network link quality parameters to construct a hierarchical storage and adaptive retransmission mechanism. This ensures that critical data is prioritized for storage and not overwritten during network fluctuations, and is retransmitted in an orderly manner according to priority when the network recovers. This achieves the effects of avoiding critical data loss, improving storage resource utilization, and ensuring data time sequence consistency. Specifically, in the data acquisition stage, regular periodic data and abnormal event data are distinguished to lay the foundation for differentiated processing. In the protocol parsing stage, a data packet containing a data type identifier is generated, enabling the microprocessor unit 100 to dynamically decide the storage priority based on the identifier. In the network status monitoring stage, the network connection status and link quality parameters are detected in real time. When the connection is normal, data is sent in real time and the space of the RAM temporary buffer 510 is released. In the anomaly handling stage, data is written to the corresponding partition of the Flash persistent storage area 530 according to the data type and network link quality parameters. For example, when the link quality parameters are low, faulty data is stored in the high-priority partition first. In the retransmission stage, the retransmission behavior is dynamically adjusted according to the current network link quality parameters and executed strictly according to the timestamp order. After each successful retransmission, the record is deleted immediately to release storage space.

[0053] In practical applications, the microprocessor unit 100 performs adaptive control based on the monitoring results of network link quality parameters. Combined with the hierarchical storage mechanism of the data storage unit 500, it ensures that critical data is stored first and not overwritten during network interruptions, and is retransmitted in an orderly manner according to priority when the network recovers. For example, when the network link quality parameters are lower than a preset threshold, the microprocessor unit 100 performs lossless differential encoding compression on the regular partition data to free up storage space and ensure the integrity of high-priority data. When the network recovers, the microprocessor unit 100 initiates the retransmission mechanism according to the real-time network link quality parameters, prioritizes reading the data of high-priority partitions and performs uploads in timestamp order, while the retransmission interval of regular partition data is dynamically adjusted according to network quality. Thus, this technical solution effectively avoids the risk of loss of critical operating status information during network fluctuations through the linkage decision-making mechanism of network link quality parameters and data types; the hierarchical storage strategy significantly improves the utilization efficiency of storage resources and prevents high-priority data from being overwritten by regular data; the retransmission process dynamically optimizes priority and interval according to network quality, reduces the probability of data misordering and reduces unnecessary traffic consumption, thereby ensuring the reliability and real-time performance of data transmission in complex electromagnetic environments for industrial monitoring systems.

[0054] This application further proposes a method for detecting network connection status and network link quality parameters, including: the microprocessor unit 100 queries the GPRS communication unit 300 for network registration status, socket connection status, and received signal strength indication value via AT commands; if N consecutive queries show that the link is disconnected or not registered, the network connection is determined to be abnormal, where N is a preset integer greater than or equal to 2; when the network link quality parameter is lower than a first preset threshold, the upload attempt interval for high-priority data is shortened and its maximum number of retries is increased.

[0055] Among them, network registration status refers to whether the GPRS communication unit 300 has successfully attached to the core network of the mobile network operator. It can be queried using standard AT commands such as AT+CREG, and its purpose is to confirm the availability of basic network access. Socket connection status refers to whether the TCP connection established with the remote monitoring terminal maintains the active state of the data transmission channel. It can be obtained using commands such as AT+CIPSTATUS, and its purpose is to monitor the connectivity of the real-time communication link. Received signal strength indication value refers to the quantitative indicator of the wireless signal strength received by the GPRS communication unit 300, usually expressed in dBm. It can be obtained through AT commands such as AT+CREG, and its purpose is to monitor the connectivity of the real-time communication link. The +CSQ command reads signals to objectively reflect the signal coverage quality under the current electromagnetic environment. N in the N consecutive queries is a configurable integer threshold, set to a value greater than or equal to 2, to filter transient interference through a time window mechanism and avoid misjudgments caused by single anomalies. The first preset threshold is a critical value for network link quality parameters, set according to the actual application scenario, to distinguish between good and bad network quality states to trigger dynamic policy adjustments. Shortening the upload attempt interval means reducing the time interval between retry operations, while increasing the maximum number of retries means allowing more retries, aiming to prioritize and strengthen the transmission resilience of high-priority data when network quality is poor.

[0056] Specifically, the solution in this application periodically sends AT commands to the GPRS communication unit 300 through the microprocessor unit 100 to query multi-dimensional network status parameters, including network registration status, socket connection status, and received signal strength indication value, thereby comprehensively and quantitatively evaluating the current network link quality. Only when the results of N consecutive queries indicate link abnormality is the network connection abnormality determined. This mechanism effectively filters out instantaneous signal fluctuations caused by base station switching or brief electromagnetic noise, ensuring that the data caching process is only initiated when the network is continuously unstable, avoiding the accidental triggering of redundant storage operations due to a single query failure. At the same time, when the network link quality parameters are detected to be lower than the first preset threshold, the upload attempt interval of high-priority data is dynamically shortened and its maximum retry count is increased, so that critical information such as fault codes can obtain more frequent transmission opportunities and longer retry windows in weak network environments, while regular periodic data maintains the standard strategy to optimize network bandwidth utilization, thereby prioritizing the reliable transmission of critical information under limited resource conditions, forming a closed-loop control logic for network status determination and transmission strategy adjustment.

[0057] As a specific implementation method, the solution of this application is implemented as follows: the microprocessor unit 100 is implemented using a microcontroller based on the ARM Cortex-M4 core, and the GPRS communication unit 300 uses an industrial-grade GSM / GPRS communication module that supports the AT command set; during the detection process, the microprocessor unit 100 queries the network registration status through the AT+CREG? command, checks the Socket connection status through the AT+CIPSTATUS command, and obtains the received signal strength indication value through the AT+CSQ command; N is set to 3, that is, when three consecutive queries are abnormal, the network connection is determined to be abnormal; when the received signal strength indication value is lower than the preset threshold, the interval for uploading high-priority data is shortened from the default value, and the maximum number of retries is increased to strengthen the transmission guarantee of critical data.

[0058] This application further proposes that in step S100 of the data transmission control method, when the Modbus interface unit 200 detects a fault code returned by the frequency converter, it triggers a hardware interrupt to the microprocessor unit 100; the microprocessor unit 100 responds to the interrupt, suspends the regular periodic reading task, and prioritizes the execution of the abnormal event data acquisition and uploading process for the fault code.

[0059] Hardware interrupts refer to an immediate response mechanism generated through dedicated signal lines. They can be implemented using level-triggered or edge-triggered interrupt signals, specifically configured as high-level active or falling-edge triggered modes. Their purpose is to ensure that fault events can be captured immediately, overcoming the periodic limitations of software polling. Dynamic adjustment of task priorities can be understood as a real-time change in runtime resource allocation strategies. Specifically, it can be achieved by modifying the priority parameters of the task scheduling queue through interrupt service routines. Its purpose is to temporarily release computing resources and communication bandwidth, establishing a dedicated channel for high-priority fault data processing.

[0060] Specifically, when the Modbus interface unit 200 identifies a specific fault code returned by the frequency converter during data interaction, it immediately sends an interrupt request signal to the microprocessor unit 100 via a hardware interrupt pin. Upon receiving the interrupt signal, the microprocessor unit 100 suspends the currently executing routine periodic data reading task and reallocates system resources to the fault handling process. Subsequently, the microprocessor unit 100 prioritizes the acquisition of abnormal event data for the fault code, including reading the operating parameters at the time of the fault occurrence, the fault type identifier, and related environmental data. This high-priority data is then encapsulated into independent data packets and uploaded to the remote monitoring terminal via the GPRS communication unit 300. This process, through the close cooperation between the interrupt mechanism and the task scheduling strategy, achieves immediate response to fault events and resource preemption, avoiding the blockage of critical information by routine data flows.

[0061] As a specific implementation, when the inverter detects a motor overheating fault during operation and returns a "0x0003" fault code, the Modbus interface unit 200 detects the abnormal value through its built-in fault code recognition circuit and immediately sends a low-level interrupt signal to the microprocessor unit 100 through a dedicated interrupt pin. After the interrupt controller of the microprocessor unit 100 captures the signal, it suspends the regular operation data acquisition task that is executed every 5 seconds and starts the fault data acquisition subroutine. It reads the fault occurrence timestamp, temperature sensor value, and motor current waveform data stored inside the inverter and packages these data into a high-priority data packet. In the data upload stage, the microprocessor unit 100 prioritizes the communication resources of the GPRS communication unit 300. Even if the current network link quality parameter is lower than the threshold, it still prioritizes the storage or real-time transmission of the fault data packet through the high-priority partition to ensure that the fault information is collected and enters the transmission queue within 300 milliseconds.

[0062] This application further proposes that the hierarchical storage in step S400 includes: judging according to the data type identifier of the data packet to be transmitted; if it is a fault code or alarm data, it is written to the high-priority partition of the Flash persistent storage area 530 and a timestamp is recorded; if it is regular periodic data, it is written to the regular partition; when the remaining space of the regular partition is insufficient, the earliest data is overwritten according to the first-in-first-out rule; when the network link quality parameter is lower than the second preset threshold, the microprocessor unit 100 performs lossless differential encoding compression on the regular periodic data before writing it to the regular partition.

[0063] Among them, data type identifier refers to the marking information used to distinguish data priority, which can be implemented by setting specific type fields or additional identifiers in the header of the data packet, with the purpose of quickly identifying key data content; high priority partition refers to the logical area in the Flash persistent storage area 530 dedicated to storing fault alarm data, which can be implemented by address range division or independent sector allocation, with the purpose of ensuring that high priority data is not overwritten; record timestamp refers to storing the time information of the data generation time together with the data, which can be obtained by the system real-time clock module, with the purpose of maintaining the data generation order; regular partition refers to the area in the Flash persistent storage area 530 used to store non-critical data, which can be a contiguous storage block, with the purpose of achieving physical isolation of data; first-in-first-out rule refers to the management mechanism that prioritizes deleting the oldest data when storage space is insufficient, which can be implemented by queue pointers or timestamp sorting, with the purpose of optimizing space utilization efficiency; lossless differential coding compression refers to the processing of compressing regular data without losing information, which can be implemented by Delta encoding or dictionary compression algorithms, with the purpose of reducing data volume to increase storage density.

[0064] Specifically, the solution in this application first automatically distinguishes data priorities based on data type identifiers, directing fault codes or alarm data to high-priority partitions in the Flash persistent storage area 530 to ensure their storage security, while storing regular periodic data in regular partitions for physical isolation; when regular partition space is insufficient, a first-in-first-out (FIFO) mechanism is used to overwrite the oldest data to maintain the timeliness of the latest data; when network link quality parameters are below a threshold, lossless differential coding compression of regular data is dynamically enabled, thereby improving storage efficiency under weak signal conditions. This hierarchical storage and dynamic adjustment mechanism works in tandem to effectively solve the problems of easy loss of critical data and low utilization of storage resources during network fluctuations.

[0065] As a preferred embodiment, the solution of this application is implemented as follows: When the microprocessor unit 100 receives a data packet containing a fault code, it writes it to the high-priority partition of the Flash persistent storage area 530, which is located in the front area of ​​the storage area; for regular operating data, it writes it to the subsequent regular partition. When the remaining space in the regular partition is insufficient, the system automatically deletes the regular data record with the earliest timestamp to free up space. When the network link quality parameter is lower than a second preset threshold, the microprocessor unit 100 performs lossless differential encoding on the regular periodic data, for example, by compressing the data by calculating the difference between adjacent data points before storing it in the regular partition.

[0066] In practical applications, some of the embodiments described above in this application propose a control command issuance process to enable remote monitoring terminals to control frequency converters. However, in the implementation process, the control command issuance lacks an effective security verification mechanism, which may lead to unencrypted commands being intercepted or forged, and the terminal identity not being reliably authenticated. This may result in the risk of the equipment being maliciously manipulated by unauthorized terminals, such as the frequency converter being started erroneously or its parameters being tampered with, causing safety hazards in industrial sites.

[0067] In response, this application further proposes a control command issuance process, such as... Figure 4 and Figure 5 As shown, the control command issuance process includes: T100, the GPRS communication unit 300 receives an encrypted control command sent by the remote monitoring terminal, the encrypted control command including terminal authentication information and command content; T200: The microprocessor unit 100 decrypts the encryption control command and verifies the legality of the terminal authentication information; if the verification fails, it refuses to execute and records the abnormal access log. After T300 verification is successful, the decrypted instruction content is converted into a Modbus protocol write instruction frame and sent to the frequency converter through the Modbus interface unit 200. T400, the microprocessor unit 100 reads the execution feedback result of the frequency converter through the Modbus interface unit 200, and transmits the execution result back to the remote monitoring terminal through the GPRS communication unit 300.

[0068] Among them, encrypted control commands refer to data packets that obfuscate the original commands using cryptographic means to prevent information leakage. These can be implemented using symmetric or asymmetric encryption algorithms, aiming to ensure the confidentiality of command transmission and prevent plaintext commands from being intercepted and directly used by third parties. Terminal authentication information can be understood as additional data used to verify the authenticity of the command sender's identity. It can be implemented using a digital certificate-based identity system or a biometric-based dynamic token mechanism, aiming to establish a trusted verification channel for terminal identity and prevent forged terminals from impersonating legitimate monitoring systems. Refusing execution and recording abnormal access logs specifically refers to terminating the command processing flow and generating security audit records when verification fails. This can be achieved by writing the log information to independent secure storage. This is achieved by using regional or external alarm interfaces to retain evidence of security incidents and support subsequent source tracing analysis, preventing unauthorized operations from causing equipment malfunction. Converting command content to Modbus protocol and writing command frames refers to adapting the decrypted control parameters to a communication format recognizable by the frequency converter. This can be achieved using protocol conversion table mapping or command template filling, ensuring compatibility between the command format and the frequency converter's communication protocol to avoid execution failure due to protocol incompatibility. Execution feedback result transmission specifically refers to returning the operation status information returned by the frequency converter to the monitoring terminal via a wireless network. This can be achieved using timestamped acknowledgment messages or error retransmission mechanisms, aiming to form a closed-loop confirmation of command execution, enabling the remote terminal to monitor the operation results in real time.

[0069] Specifically, in this application, after receiving the encrypted control command via the GPRS communication unit 300, the microprocessor unit 100 immediately initiates the decryption process and simultaneously verifies the legality of the terminal authentication information. This verification process is based on a preset security policy to determine the source of the command in real time. If the verification is successful, the microprocessor unit 100 converts the decrypted command content into a Modbus protocol write command frame that meets the requirements of the frequency converter and sends it to the frequency converter for execution via the Modbus interface unit 200, while simultaneously initiating a feedback monitoring mechanism. When the frequency converter returns the execution result, the microprocessor unit 100 reads the result via the Modbus interface unit 200 and transmits it back to the remote monitoring terminal via the GPRS communication unit 300, thereby completing the complete closed loop of command issuance. If the verification fails, the microprocessor unit 100 directly refuses to execute the command and writes the abnormal information into the security log to prevent illegal commands from affecting equipment operation. This process constructs an end-to-end security control chain through the organic integration of encrypted transmission, identity authentication, anomaly interception, and status feedback. The encryption and authentication links support each other to ensure the credibility of the command source, the refusal to execute and logging form a security fallback mechanism, and the feedback transmission ensures the traceability of the operation. Overall, it realizes full-process security control of control commands from reception, verification to execution and confirmation.

[0070] As a specific implementation method, the solution of this application is implemented as follows: The microprocessor unit 100 adopts an ARM Cortex-M7 architecture microcontroller with an integrated hardware encryption engine. The GPRS communication unit 300 accesses the mobile network through a standard SIM card interface. When it receives an AES-256 encrypted control command sent by the remote monitoring terminal, the microprocessor unit 100 calls the built-in hardware encryption module to decrypt it and verifies the terminal authentication information based on the preset terminal identifier database. After successful verification, the decryption command is converted into a write command frame in Modbus RTU format and sent to the inverter via the RS485 physical layer of the Modbus interface unit 200. After the inverter executes the command, it returns a response message containing an operation status code. The microprocessor unit 100 captures the message through the Modbus interface unit 200 and transmits it back to the monitoring terminal via the GPRS communication unit 300 using the HTTPS protocol. If the terminal authentication information verification fails, the microprocessor unit 100 writes the abnormal access log to the independent security partition of the data storage unit 500 and triggers the LED alarm indicator to flash.

[0071] Through the above solution, this application effectively solves the problem of unauthorized operation of equipment caused by the lack of security verification of control commands, ensures the confidentiality and reliability of command transmission, prevents the risk of inverter misoperation caused by command interception or forgery, and provides technical support for security audit through the abnormal log recording mechanism, significantly improving the security and controllability of remote control in industrial sites.

[0072] This application further proposes that in step T200, the terminal authentication information includes a terminal identifier, a timestamp, and a message authentication code based on a shared key, and the microprocessor unit 100 uses a built-in hardware encryption module to verify the message authentication code.

[0073] Among them, the terminal identifier refers to the information that uniquely identifies the remote monitoring terminal, which can be implemented using the device serial number, IMEI number, or a preset unique ID. Its purpose is to ensure the legitimacy of the command source and prevent unauthorized devices from accessing the system. The timestamp refers to the information that records the time point when the command was generated. It can be implemented using a standard timestamp format or a custom time encoding. Its purpose is to provide a freshness verification benchmark for the command and effectively prevent the reuse of historical commands. The message authentication code based on the shared key refers to the verification value generated by the encryption algorithm using the pre-shared key. It can be implemented using standard algorithms such as HMAC-SHA256 or CMAC-AES. Its purpose is to ensure the integrity and authenticity of the command content during transmission and prevent data tampering. The verification of the hardware encryption module refers to the verification process of the message authentication code performed by the dedicated hardware circuit. It can be implemented using an encryption coprocessor integrated in the microprocessor or a dedicated MAC verification unit. Its purpose is to improve verification efficiency and security and avoid performance delays and security vulnerabilities that may be introduced by software implementation.

[0074] Specifically, when the microprocessor unit 100 receives an encryption control command, in step T200, it first extracts the terminal identifier, timestamp, and message authentication code from the terminal authentication information. Then, it uses a built-in hardware encryption module to verify the message authentication code, confirming the integrity and authenticity of the command content. Simultaneously, it judges the freshness of the command based on the timestamp, ensuring it is within a preset valid time window. If the message authentication code verification passes and the timestamp is valid, the terminal authentication information is confirmed as legitimate, and the command is allowed to continue execution; otherwise, execution is refused, and an abnormal access log is recorded. This design, through the organic combination of terminal identifier verification of source legitimacy, timestamp ensuring command timeliness, message authentication code ensuring content integrity, and hardware encryption module accelerating the verification process, forms a multi-layered security protection mechanism, effectively blocking the implementation paths of replay attacks and forged commands.

[0075] As a specific implementation method, this application is implemented as follows: the terminal identifier can be a unique device serial number of the remote monitoring terminal; the timestamp can be a standard time representation based on Coordinated Universal Time; the message authentication code can be an HMAC value generated using a pre-shared key and a standard encryption algorithm; the hardware encryption module in the microprocessor unit 100 can be an integrated encryption coprocessor used to efficiently perform the message authentication code verification operation.

[0076] This application further proposes a remote parameter configuration process: the microprocessor unit 100 receives configuration parameters sent by the remote monitoring terminal through the GPRS communication unit 300. The configuration parameters include Modbus baud rate, protocol type, data reading cycle, server IP address and port number; the microprocessor unit 100 writes the received configuration parameters into the EEPROM configuration storage area 520 and loads and takes effect on the next power-on.

[0077] Among them, the microprocessor unit 100 is the core component that executes data processing and control logic. It can be implemented using a microcontroller with an ARM Cortex-M7 architecture. Its purpose is to centrally manage the reception, storage, and application of configuration parameters. The GPRS communication unit 300 can be understood as a module that realizes wireless data transmission. Specifically, it can be implemented using a SIM7600 series 4G module. Its purpose is to establish a stable communication link with the remote monitoring terminal and ensure that configuration parameters can be reliably transmitted through the existing wireless network. Configuration parameters refer to the data set used to define communication protocols and network connection characteristics. They can include parameters such as Modbus baud rate, protocol type, data reading cycle, server IP address, and port number. Their purpose is to adapt to different frequency converters and network environments and avoid communication failures caused by parameter mismatch. The EEPROM configuration storage area 520 can be understood as part of the non-volatile storage medium. Specifically, it can be implemented by an external I²C interface EEPROM chip extended by the microcontroller. Its purpose is to persistently save configuration parameters, ensure that data is not lost after power failure, and provide a reliable parameter storage foundation for the system.

[0078] Specifically, the solution in this application involves a microprocessor unit 100 continuously monitoring the data stream received by the GPRS communication unit 300. When a configuration parameter packet containing a specific identifier is detected, its integrity is verified and decrypted. After successful verification, the parameter content is written to the EEPROM configuration storage area 520 for persistent storage, but does not take effect immediately. The system maintains the current operating parameters unchanged until the device is powered on again after a normal shutdown. At this time, the microprocessor unit 100 reads the latest configuration parameters from the EEPROM configuration storage area 520 and initializes the relevant communication modules, thereby achieving a smooth parameter switching. This design avoids protocol parsing errors or communication interruptions that may be caused by modifying parameters during operation, especially in the critical retransmission phase after network recovery, ensuring the continuity and stability of the data transmission process.

[0079] As a specific implementation method, this application is implemented as follows: the microprocessor unit 100 can adopt an NXP.MXRT1062 crossover microcontroller, whose built-in hardware encryption module supports the national cryptographic SM4 algorithm; the GPRS communication unit 300 is connected to the microprocessor unit 100 through a serial peripheral interface; the EEPROM configuration storage area 520 is implemented by an external 24LC256 serial EEPROM chip and is used to store configuration parameters; when the remote monitoring terminal sends a configuration update command, the microprocessor unit 100 verifies the terminal authentication information and writes the new parameters to the specified storage address. After the device restarts, the new parameters are automatically loaded, for example, the data reading cycle is adjusted from 5 seconds to 10 seconds to reduce network traffic consumption.

[0080] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A GPRS-based bidirectional communication module card for frequency converters, characterized in that, include: The microprocessor unit has a built-in hardware CRC check module and a hardware encryption module, which are used to perform data protocol conversion, data encryption and decryption, network link quality parameter monitoring, and adaptive data storage and retransmission control based on the network link quality parameters. The Modbus interface unit connects to the Modbus communication port of the frequency converter and is used to receive the operating data output by the frequency converter and send control commands to the frequency converter. The GPRS communication unit is used to establish a connection with the GPRS mobile network, send the data packets to be transmitted to the remote monitoring terminal, receive control commands issued by the remote monitoring terminal, and provide the current network link quality parameters to the microprocessor unit. The data storage unit includes a RAM temporary cache area, an EEPROM configuration storage area, and a Flash persistent storage area. The Flash persistent storage area is divided into a high-priority partition and a regular partition, which are used to hierarchically store data packets that failed to be uploaded according to the data type and the network link quality parameters. The power management unit is connected to the inverter's power supply system and is used to provide a stable operating voltage to each unit.

2. The GPRS-based bidirectional communication module card for frequency converters according to claim 1, characterized in that, The microprocessor unit has a built-in network state machine, which includes online state, offline state and recovery state. When offline, the microprocessor unit directs the data to be transmitted to the corresponding partition of the Flash persistent storage area; When switching to recovery state, a retransmission thread is started according to the network link quality parameters at that time, and the unsuccessfully uploaded data stored in the Flash persistent storage area is read and uploaded according to the timestamp order and the priority weighting rule positively correlated with the network link quality parameters. The better the network link quality parameters, the shorter the retransmission interval of high priority partition data.

3. The GPRS-based bidirectional communication module card for frequency converters according to claim 1, characterized in that, The Modbus interface unit supports Modbus RTU, Modbus ASCII and Modbus TCP protocols, and protocol switching can be achieved through hardware DIP switches or software configuration. The baud rate supports adaptive matching with the inverter communication parameters.

4. A data transmission control method based on the communication module card according to any one of claims 1 to 3, characterized in that, This includes a data upload process, which includes: S100. The Modbus interface unit collects operating data from the frequency converter according to a preset reading cycle. The operating data includes regular periodic data and abnormal event data. S200: The microprocessor unit performs protocol parsing and format conversion on the collected running data to generate a data packet to be transmitted containing a data type identifier; S300: The microprocessor unit detects the network connection status of the GPRS communication unit and the network link quality parameters. When the network connection is normal, it sends the data packet to be transmitted to the remote monitoring terminal in real time, and after receiving the confirmation response, it marks it as sent and releases the corresponding storage space in the RAM temporary buffer area. S400. When the network connection is abnormal or the transmission fails, the data packet to be transmitted, along with the timestamp and the failure reason code, is written into the corresponding partition of the Flash persistent storage area according to the data type and the network link quality parameters at that time. S500. When the GPRS communication unit is detected to have restored the network connection, the microprocessor unit reads the data that was not successfully uploaded from the Flash persistent storage area according to the current network link quality parameters and performs retransmission in the order of timestamps. After each data is successfully retransmitted and an acknowledgment is received, the corresponding record is deleted from the Flash persistent storage area.

5. The data transmission control method according to claim 4, characterized in that, In step S300, detecting the network connection status and the network link quality parameters includes: the microprocessor unit queries the GPRS communication unit for network registration status, socket connection status, and received signal strength indication value via AT commands; if N consecutive queries show that the link is disconnected or not registered, the network connection is determined to be abnormal, where N is a preset integer greater than or equal to 2; when the network link quality parameter is lower than a first preset threshold, the upload attempt interval for high-priority data is shortened and its maximum retry count is increased.

6. The data transmission control method according to claim 4, characterized in that, In step S100, when the Modbus interface unit detects a fault code returned by the frequency converter, it triggers a hardware interrupt to the microprocessor unit; the microprocessor unit responds to the interrupt, suspends the regular periodic reading task, and prioritizes the execution of the abnormal event data acquisition and uploading process for the fault code.

7. The data transmission control method according to claim 4, characterized in that, The hierarchical storage in step S400 includes: judging based on the data type identifier of the data packet to be transmitted; if it is a fault code or alarm data, it is written to the high-priority partition of the Flash persistent storage area and a timestamp is recorded; if it is regular periodic data, it is written to the regular partition; when the remaining space of the regular partition is insufficient, the earliest data is overwritten according to the first-in-first-out rule; when the network link quality parameter is lower than the second preset threshold, the microprocessor unit performs lossless differential encoding compression on the regular periodic data before writing it to the regular partition.

8. The data transmission control method according to claim 4, characterized in that, It also includes a control command issuance process, which includes: T100, The GPRS communication unit receives an encrypted control command sent by the remote monitoring terminal, the encrypted control command including terminal authentication information and command content; T200: The microprocessor unit decrypts the encryption control command and verifies the legality of the terminal authentication information; if the verification fails, it refuses to execute and records the abnormal access log. After T300 verification is successful, the decrypted instruction content is converted into a Modbus protocol write instruction frame and sent to the frequency converter through the Modbus interface unit. T400: The microprocessor unit reads the execution feedback result of the frequency converter through the Modbus interface unit, and transmits the execution result back to the remote monitoring terminal through the GPRS communication unit.

9. The data transmission control method according to claim 8, characterized in that, In step T200, the terminal authentication information includes a terminal identifier, a timestamp, and a message authentication code based on a shared key. The microprocessor unit uses the built-in hardware encryption module to verify the message authentication code.

10. The data transmission control method according to claim 4, characterized in that, It also includes a remote parameter configuration process: the microprocessor unit receives configuration parameters sent by the remote monitoring terminal through the GPRS communication unit. The configuration parameters include Modbus baud rate, protocol type, data reading cycle, server IP address and port number; the microprocessor unit writes the received configuration parameters into the EEPROM configuration storage area and loads and makes them effective on the next power-on.

Images