Aluminum electrolysis cell shell temperature monitoring system

Abstract

The utility model discloses an aluminum electrolysis cell shell temperature monitoring system, which comprises a monitoring client, a cell shell temperature monitoring cloud platform and a plurality of local acquisition and control units, and each local acquisition and control unit comprises a plurality of temperature sensors and a plurality of heat dissipation modules; and each on-site acquisition and control unit acquires temperature data of key point positions of the electrolytic cell shell in real time through the temperature sensor, accurately controls the work of the heat dissipation module according to a preset temperature threshold value, and monitors the state of the heat dissipation module. According to the scheme, the problems of exception handling lag and information isolated island of traditional aluminum electrolysis cell shell temperature monitoring can be solved. Automatic temperature adjustment can be achieved, production risks caused by manual delay are avoided, data are integrated, barriers are broken, enterprises are helped to optimize the process, energy is saved, efficiency is improved, the electrolytic aluminum efficiency is effectively improved, intelligent transformation of the industry is promoted, and competitiveness is improved.

Description

Technical Field

[0001] This invention relates to the field of sensor control technology, specifically to a temperature monitoring system for an aluminum electrolysis cell shell. Background Technology

[0002] In the aluminum electrolysis industry, the aluminum electrolysis cell plays a crucial role in the production process, and the cell shell temperature, as a core indicator reflecting its operating status, has a profound impact on the stability and efficiency of the entire production process. Currently, monitoring the shell temperature of aluminum electrolysis cells mainly relies on traditional detection methods. These traditional systems mostly focus only on temperature data collection and detection, with relatively limited functionality. When abnormal temperatures are detected, there is a lack of automatic intervention mechanisms, making it impossible to take timely and effective measures such as adjusting the electrolysis cell's operating parameters or activating cooling equipment. Instead, they can only passively wait for manual intervention, which undoubtedly increases the risk of production accidents caused by abnormal temperatures, potentially leading to damage to the aluminum electrolysis cell, production interruptions, and a significant increase in costs.

[0003] For example, the utility model patent CN208201144U discloses a device for measuring the temperature of the bottom and side of an aluminum electrolytic cell, including a temperature acquisition module, a data transmission module, a data conversion module, and a controller connected in sequence. At least three temperature acquisition modules are respectively installed on the bottom outer wall and the two side outer walls of the electrolytic cell, with the cathode steel rod located within the electrolytic cell in the mapping area of ​​the bottom outer wall and the two side outer walls. The controller includes a CPU containing an ambient temperature detection sensor. Based on this structure, the measuring device can achieve real-time, automatic, and reliable measurement of the bottom and side temperatures of the aluminum electrolytic cell, thereby enabling real-time temperature monitoring and preventing the safety hazard of cell exposure due to excessively high temperatures at the bottom or sides during aluminum electrolytic cell production. However, such traditional temperature monitoring systems suffer from serious information silos. Temperature data collected from various monitoring points or areas are often stored and used in isolation, failing to achieve effective data sharing and interaction with other related systems in the aluminum electrolysis production process, such as the electrolytic cell control system and the energy management system. This fragmented information makes it difficult for enterprises to grasp the overall production and operation status and fully explore the correlation information between temperature data and other production links. This hinders the optimization of production processes, the efficient use of energy, and the formulation of intelligent management decisions, which is not conducive to the transformation and upgrading of the aluminum electrolysis industry towards an efficient, precise, and intelligent production model. Summary of the Invention

[0004] To address the problems mentioned in the background, this solution provides an aluminum electrolysis cell shell temperature monitoring system, resolving the issues of delayed anomaly handling and information silos in traditional aluminum electrolysis cell shell temperature monitoring. This system can automatically adjust the temperature, avoiding production risks caused by manual delays, and can also integrate data, breaking down barriers to help enterprises optimize processes, save energy and increase efficiency, promote the intelligent transformation of the industry, and enhance competitiveness.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: an aluminum electrolysis cell shell temperature monitoring system, including a monitoring client, a cell shell temperature monitoring cloud platform, and several local data acquisition and control units. Each local data acquisition and control unit includes several temperature sensors and several heat dissipation modules. Each local data acquisition and control unit acquires high-precision temperature data of key points of the electrolysis cell shell in real time through the temperature sensors, accurately controls the start and stop operation of the heat dissipation modules according to preset temperature thresholds, and monitors the status of the heat dissipation modules. All local data acquisition and control units receive control commands from the monitoring gateway through a fieldbus, and stably and quickly transmit the status information of the temperature sensors and the heat dissipation modules to the monitoring gateway. The monitoring gateway pollutes the temperature and status information acquired by the local data acquisition and control units, and transmits the data status information to the cell shell temperature monitoring cloud platform through network transmission equipment via Ethernet or GPRS / 3G / 4G / 5G networks. At the same time, the control commands of the cell shell temperature monitoring cloud platform are forwarded to the local data acquisition and control units. The cell shell temperature monitoring cloud platform is connected to the monitoring client.

[0006] Furthermore, the cell shell temperature monitoring cloud platform includes a monitoring equipment management module, a monitoring data management module, a system platform management module, and a system monitoring management module. The monitoring equipment management module includes an electrolytic cell management unit, a monitoring gateway management unit, and a local data acquisition and control unit management unit. The monitoring data management module includes a data display unit and a data storage unit. The system platform management module includes a user management unit, a log management unit, a database management unit, and a message server management unit. The system monitoring management module includes a traffic monitoring unit and an online user monitoring unit. This cell shell temperature monitoring cloud platform integrates data processing (receiving, forwarding, and storing), real-time monitoring and visualization, data analysis and intelligent diagnosis, management of historical data and user permissions, remote control, and system management, providing convenient, efficient, and secure aluminum electrolytic cell monitoring services for different monitoring client users.

[0007] Furthermore, the monitoring client supports desktop and various mobile operating systems, providing users with electrolytic cell equipment management and monitoring services via a B / S (Browser / Server) architecture. The monitoring client includes an administrator client, a shift worker client, a device debugging or maintenance worker client, and a third-party platform client. These clients can be mobile devices such as iPads, tablets, and mobile phones, or personal computers.

[0008] Furthermore, the temperature sensor is preferably a PT100 temperature sensor, which utilizes the characteristic that the resistance of platinum changes with temperature to measure temperature. Its measurement range is -55℃ to 600℃, with an error of ±0.1℃. The heat dissipation module employs both air-cooling devices (such as cooling fans) and / or liquid-cooling devices (such as a cooling solenoid valve mechanism), and its start and stop are controlled by switching signals, supporting operational status feedback.

[0009] Furthermore, the local data acquisition and control unit is connected to temperature sensors and heat dissipation modules via high-temperature resistant cables to acquire high-precision temperature data at key points on the electrolytic cell shell in real time. Based on preset temperature thresholds, it precisely controls the start and stop operation of the heat dissipation module and monitors its status. In system application, the electrolytic cell shell is divided into several monitoring areas, each corresponding to an independent data acquisition and control channel. Each data acquisition and control channel includes one temperature sensor and one heat dissipation module. Preferably, each local data acquisition and control unit can manage up to eight data acquisition and control channels. That is, each local data acquisition and control unit includes up to eight temperature sensors and eight heat dissipation modules.

[0010] Furthermore, each of the local data acquisition and control units has a 12-byte unique identification code (UID). Administrators or users with equipment commissioning / maintenance permissions can create or edit target aluminum electrolysis cell objects (monitoring gateways) in the cell shell temperature monitoring cloud platform and bind multiple local data acquisition and control units to them.

[0011] Furthermore, an RS485 / CAN bus is preferably used as the fieldbus to form a communication network between the monitoring gateway of the designated electrolytic cell and the local data acquisition and control unit. Each electrolytic cell corresponds to one monitoring gateway, and the electrolytic cell shell is divided into multiple independent monitoring areas. One local data acquisition and control unit can monitor up to eight monitoring areas (one data acquisition and control channel corresponds to one monitoring area). The monitoring gateway is the master, and the local data acquisition and control unit is the slave. When using RS485 bus communication, the application layer uses the ModBus-RTU standard protocol to exchange data.

[0012] Furthermore, the monitoring gateway has a 12-byte unique identifier (UID). The monitoring gateway and the tank temperature monitoring cloud platform exchange data using the MQTT protocol. When the monitoring gateway connects to the tank temperature monitoring cloud platform, it uses the UID as the client ID; other basic information for connecting to the tank temperature monitoring cloud platform should be configured offline.

[0013] Furthermore, in terms of hardware design, each of the local data acquisition and control units includes a controller (MCU), a temperature measurement module circuit, a display module circuit, and a button module circuit, and the controller is connected to the heat dissipation module, the temperature measurement module circuit, the display module circuit, and the button module circuit.

[0014] Furthermore, this solution preferentially uses the GD32G553 microcontroller as the core controller, with a main frequency of 180MHz, a computing power of 244DMIPS, a state-of-the-art Cortex-M33 core, powerful peripheral support, and an NPU, especially powerful floating-point processing capabilities. It has a built-in hardware multiplier / divider and provides a complete DSP instruction set and a single-precision floating-point unit (FPU). It is also equipped with a brand-new hardware trigonometric function accelerator (TMU), which supports vector, sine, cosine, exponential, square root, and common logarithmic mathematical trigonometric operations to reduce the burden of logical operations and improve processing efficiency, thereby promoting advanced computing applications centered on digital signal processing. Due to its superior performance in industrial real-time monitoring, it is widely used in high-speed AD acquisition, PWM, and other industrial applications.

[0015] Furthermore, the temperature measurement module circuit consists of a small signal processing circuit, a signal amplification circuit, a multi-channel circuit, and the temperature sensor. This module circuit amplifies the signal from the temperature sensor for data processing by the controller (microcontroller) ADC. The button module circuit allows switching modes and setting upper and lower limits for preset temperature thresholds. The display module circuit includes a display screen module and an LED display module. The display screen module shows the temperature measured by the current temperature measurement module circuit, the upper and lower threshold values, and the mode. When the temperature measured by the temperature measurement module circuit is lower than the set lower limit, the green LED of the LED display module lights up; when the temperature measured by the temperature measurement module circuit is higher than the upper limit temperature, the red LED of the LED display module lights up.

[0016] The beneficial effects of this invention are as follows: This design adopts advanced sensing technology, which can withstand the harsh environment of aluminum electrolysis cells and accurately collect temperature data of key parts of the cell shell. The heat dissipation module supports various cooling facilities to provide effective cooling for the electrolysis cell shell. The local data acquisition and control unit acquires high-precision temperature data of key points of the electrolysis cell shell in real time through temperature sensors, accurately controls the start and stop operation of the heat dissipation module according to preset temperature thresholds, and monitors the status of the heat dissipation module. The local data acquisition and control unit receives control commands from the monitoring gateway through the fieldbus and transmits the cell shell temperature and heat dissipation module status information to the monitoring gateway stably and quickly. The monitoring gateway pollutes the temperature and status information acquired by the local data acquisition and control unit and transmits the data status information to the monitoring cloud platform through network transmission equipment via Ethernet or GPRS / 3G / 4G / 5G networks. This solves the problems of delayed abnormal processing and information silos in traditional aluminum electrolysis cell shell temperature monitoring. It can automatically adjust the temperature, avoid the production risks caused by manual delays, integrate data, break down barriers, help enterprises optimize processes, save energy and increase efficiency, effectively improve the efficiency of aluminum electrolysis, promote the intelligent transformation of the industry, and enhance competitiveness. Attached Figure Description

[0017] Figure 1 This is a system structure block diagram of the present invention;

[0018] Figure 2 This is a structural block diagram of the tank shell temperature monitoring cloud platform of the present invention;

[0019] Figure 3 This is a schematic block diagram of the acquisition and control channel of the present invention;

[0020] Figure 4 This is a block diagram of the fieldbus topology of the present invention;

[0021] Figure 5 This is a schematic diagram of the monitoring gateway configuration sequence of the present invention;

[0022] Figure 6 This is a structural block diagram of the local data acquisition and control unit of the present invention;

[0023] Figure 7 The circuit diagram of the PT100 constant current source of the present invention is shown below;

[0024] Figure 8 This is a circuit diagram of the signal amplification circuit of the present invention;

[0025] Figure 9 This is a circuit diagram of the display module of the peripheral device of the present invention;

[0026] Figure 10 This is a circuit diagram of the communication module of the peripheral device of the present invention.

[0027] Figure 11 This is a circuit diagram of the sound and light alarm circuit module of the peripheral device of the present invention;

[0028] Figure 12 This is a circuit diagram of the button module of the peripheral device of the present invention;

[0029] Figure 13 This is a schematic diagram of the measurement principle of the PT100 sensor of the present invention;

[0030] Figure 14 This is a circuit diagram of the 3-wire measurement circuit of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to embodiments. It is worth noting that these specific embodiments are merely representative embodiments of the present invention, and the specific methods, apparatuses, conditions, materials, etc., exemplified are not intended to limit the present invention or the corresponding specific embodiments.

[0032] A temperature monitoring system for the shell of an aluminum electrolysis cell, such as Figure 1 As shown, the system includes a monitoring client, a cell shell temperature monitoring cloud platform, and several local data acquisition and control units. Each local data acquisition and control unit includes several temperature sensors and several heat dissipation modules. Each local data acquisition and control unit acquires high-precision temperature data of key points in the electrolytic cell shell in real time through the temperature sensors, precisely controls the start and stop operation of the heat dissipation modules according to preset temperature thresholds, and monitors the status of the heat dissipation modules. All local data acquisition and control units receive control commands from the monitoring gateway via a fieldbus and transmit the status information of the temperature sensors and the heat dissipation modules stably and quickly to the monitoring gateway. The monitoring gateway polls the temperature and status information acquired by the local data acquisition and control units and transmits the data status information to the cell shell temperature monitoring cloud platform via Ethernet or GPRS / 3G / 4G / 5G networks through network transmission equipment. At the same time, the control commands of the cell shell temperature monitoring cloud platform are forwarded to the local data acquisition and control units. The cell shell temperature monitoring cloud platform is connected to the monitoring client.

[0033] Furthermore, the monitoring client supports desktop and various mobile operating systems, providing users with electrolytic cell equipment management and monitoring services via a B / S (Browser / Server) architecture. The monitoring client includes administrator clients, shift operator clients, equipment debugging or maintenance personnel clients, and third-party platform clients.

[0034] Administrator client: Responsible for user management, electrolytic cell configuration management, and registration and deletion of monitoring gateways and local acquisition and control unit devices.

[0035] The duty officer client, in addition to having the ability to subscribe to, query and access monitoring data from third-party platforms, can also control the working mode and start / stop of the heat dissipation module.

[0036] Equipment commissioning or maintenance personnel client: In addition to having the permissions of a duty officer, it also has the permission to configure parameters of registered monitoring gateways and local acquisition and control units, and can modify the binding relationship of related equipment in the electrolytic cell.

[0037] Third-party platform clients: have the right to subscribe to real-time monitoring data and the right to query and access historical monitoring data.

[0038] The administrator client, duty officer client, equipment debugging or maintenance personnel client, and third-party platform client can be mobile devices, such as iPads, tablets, and mobile phones, or personal computers.

[0039] Furthermore, such as Figure 2 As shown, the tank shell temperature monitoring cloud platform includes a monitoring equipment management module, a monitoring data management module, a system platform management module, and a system monitoring management module.

[0040] The monitoring equipment management function module includes:

[0041] Electrolytic Cell Management Unit: Configures the number and location information of monitoring areas for the electrolytic cell shell, groups the electrolytic cells, binds the monitoring gateway, and binds the local data acquisition and control unit to the monitoring area. It allows manual control of the heat dissipation module's operating mode and start / stop via the monitoring area.

[0042] Monitoring Gateway Management Unit: This unit monitors the registration, deletion, querying, and modification of gateway parameters.

[0043] Local sampling and control unit management unit: Registration, deletion, query and modification of local sampling and control unit parameters.

[0044] The monitoring data management function module includes:

[0045] Data display unit: Displays the temperature and heat dissipation module status of the electrolytic cell shell monitoring area graphically, and shows the online status of the monitoring gateway. Historical data can be queried and displayed.

[0046] Data storage unit: Data is stored using a relational database. Data retention period is no less than 3 months.

[0047] The system platform management function module includes:

[0048] User Management Unit: This unit is responsible for the creation and maintenance of system users. It includes basic user information and permission allocation.

[0049] Log Management Unit: Records user login logs, operation logs, and system fault logs.

[0050] Database Management Unit: Configures and manages the database for monitoring and log data storage.

[0051] Message Server Management Unit: Manages the configuration of the message server and is used to monitor the information exchange between the gateway and the tank temperature monitoring cloud platform through the message server.

[0052] The system monitoring and management function module includes:

[0053] Traffic monitoring unit: Monitors the data traffic of the monitoring gateway daily. Monitors SIM card traffic and reminds users to pay bills.

[0054] Online user monitoring unit: Monitors online users, including username, IP address, client hardware and operating system type.

[0055] The cell shell temperature monitoring cloud platform integrates data processing (receiving, forwarding, and storing), real-time monitoring and visualization, data analysis and intelligent diagnosis, management of historical data and user permissions, remote control and system management, and can provide convenient, efficient and secure aluminum electrolysis cell monitoring services for different monitoring client users.

[0056] Furthermore, the temperature sensor is preferably a PT100 temperature sensor, which utilizes the characteristic that the resistance of platinum changes with temperature to measure temperature. Its measurement range is -55℃ to 600℃, and its error is ±0.1℃.

[0057] Furthermore, the heat dissipation module adopts two types: air cooling device (such as a cooling fan) and / or liquid cooling device (such as a cooling solenoid valve mechanism), and its start and stop are controlled by switching signals, and it supports working status feedback.

[0058] Furthermore, the local data acquisition and control unit is connected to a temperature sensor and a heat dissipation module via a high-temperature resistant cable to acquire high-precision temperature data at key points on the electrolytic cell shell in real time. Based on a preset temperature threshold, it precisely controls the start and stop operation of the heat dissipation module and monitors its status. Figure 3 As shown, in the system application of this embodiment, the electrolytic cell shell is divided into several monitoring areas, each corresponding to an independent data acquisition and control channel. Each data acquisition and control channel includes one temperature sensor and one heat dissipation module. Preferably, each local data acquisition and control unit can manage up to eight data acquisition and control channels. That is, each local data acquisition and control unit includes up to eight temperature sensors and eight heat dissipation modules.

[0059] Each of the local data acquisition and control units has a unique 12-byte identification code (UID). Administrators or users with equipment commissioning / maintenance permissions can create or edit a target aluminum electrolysis cell object (monitoring gateway) in the cell shell temperature monitoring cloud platform and bind multiple local data acquisition and control units to it. The configuration and control attributes of each local data acquisition and control unit include:

[0060] Address: The communication address of the local data acquisition and control unit in the fieldbus.

[0061] Baud rate: The communication baud rate of the local acquisition and control unit in the fieldbus.

[0062] Equipment Modes: The local data acquisition and control unit currently described includes three operating modes: automatic, manual off, and manual on. In automatic mode, the data acquisition and control channels operate according to their respective configured sampling channel operating modes. In manual off / on mode, all data acquisition and control channels under the local data acquisition and control unit are forced to output off / on control signals and no longer accept control commands from the data acquisition and control channels of the tank temperature monitoring cloud platform. This mode is mainly used for on-site commissioning and maintenance scenarios.

[0063] Management of acquisition and control channels: These channels are enabled or disabled based on site requirements. Disabled acquisition and control channels will no longer acquire temperature and cooling equipment status and will maintain their output control signals on the safe side.

[0064] Temperature compensation value: Actual temperature = Temperature measurement value + Temperature compensation value.

[0065] Preset temperature threshold: Temperature threshold, hysteresis value. When the data acquisition and control channel is active, the cooling module will activate when the channel temperature exceeds the upper temperature limit and will deactivate when it falls below the lower temperature limit. Upper temperature limit = Temperature threshold; Lower temperature limit = Temperature threshold - Hysteresis value.

[0066] Sampling Channel Operating Modes: The sampling channel operates in three modes: automatic, manual off, and manual on. Automatic Mode: When the sampling and control channel is active, it precisely controls the start and stop of the heat dissipation module based on a preset temperature threshold and control algorithm. Manual Off / On Mode: The sampling and control channel forcibly outputs an off / on control signal. This function is used by operators and above-level authorized users to control the output signals of the sampling and control channel on a per-channel basis.

[0067] The tank shell temperature monitoring cloud platform sends the latest configuration and control attributes to the local acquisition and control unit for persistent storage, so that it can maintain its original working state after power failure and reset.

[0068] The sampling and conversion of temperature values ​​for each sampling channel of the local sampling and control unit shall not exceed 50 milliseconds, and the total for all 8 channels shall not exceed 500 milliseconds.

[0069] The local sampling and control unit should complete the execution within 3 seconds.

[0070] The local acquisition and control unit supports in-application programming (IAP) and equipment reset commands, enabling remote single-point / batch firmware upgrades for the tank temperature monitoring cloud platform.

[0071] In addition to the program watchdog timer, the local data acquisition and control unit also has a communication timeout watchdog timer. If no command is received from the monitoring gateway via the fieldbus for more than 30 seconds, the communication watchdog timer resets.

[0072] The local data acquisition and control unit panel has operation indicators, power indicators, communication transceiver indicators, mode indicators, and fault alarm information.

[0073] When the local data acquisition and control unit's data acquisition and control channel is active and in automatic mode, if the temperature sensor malfunctions, the channel sensor malfunction will be reported, and the heat dissipation module will be ensured to be on the safe side.

[0074] During a power outage of the local acquisition and control unit, the heat dissipation module is on the safe side.

[0075] Note 1: The acquisition control channel is effective - the acquisition control channel is enabled, the local acquisition control unit is in automatic mode, and the acquisition control channel is also in automatic mode.

[0076] Note 2: Safety side - Based on the fail-safe principle, starting the heat dissipation module is the safety side.

[0077] Furthermore, such as Figure 4 As shown, in this embodiment, the system uses an RS485 / CAN bus to form a communication network between the monitoring gateway of a designated electrolytic cell and the local data acquisition and control unit. Each electrolytic cell corresponds to one monitoring gateway, and the electrolytic cell shell is divided into multiple independent monitoring areas. One local data acquisition and control unit can monitor up to eight monitoring areas (one data acquisition and control channel corresponds to one monitoring area). The monitoring gateway is the master, and the local data acquisition and control unit is the slave. When using RS485 bus communication, the application layer uses the ModBus-RTU standard protocol to exchange data. The communication content is shown in the table below:

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084] Furthermore, the monitoring gateway is primarily responsible for polling the temperature and status information acquired by the local data acquisition and control unit, and transmitting the data status information to the monitoring cloud platform via Ethernet or GPRS / 3G / 4G / 5G networks through network transmission equipment. Simultaneously, it forwards control commands from the cloud platform to the local data acquisition and control unit. The monitoring gateway has a 12-byte unique identifier (UID). The monitoring gateway interacts with the cloud platform using the MQTT protocol. When connecting to the cloud platform, the monitoring gateway uses the UID as the client ID; other basic information for connecting to the cloud platform should be configured offline. Administrators or equipment debugging / maintenance personnel can create or edit target aluminum electrolysis cell objects in the cloud platform; this process involves creating or editing the monitoring gateway. The basic attributes of the monitoring gateway are as follows:

[0085] Address: The communication address of the monitoring gateway in the fieldbus.

[0086] Baud rate: The communication baud rate of the monitoring gateway in the fieldbus.

[0087] Local data acquisition and control unit list: Each row in the list represents a local data acquisition and control unit bound to the monitoring gateway. After initializing the settings of the bound local data acquisition and control units, the monitoring gateway establishes a polling list to obtain data and status information in real time.

[0088] List item fields include:

[0089] Local data acquisition and control unit number: This number will be included in the subscription or publication topic string between the monitoring gateway and the cloud platform to identify the local data acquisition and control unit.

[0090] Local sampling and control unit UID: A globally unique identifier for the local sampling and control unit.

[0091] Local data acquisition and control unit address: The communication address of the local data acquisition and control unit in the fieldbus.

[0092] Fieldbus: Select the fieldbus connected to the local data acquisition and control unit. For example: COM1 / COM2 / CAN1 / CAN2.

[0093] like Figure 5 As shown, the monitoring gateway obtains configuration and operation instructions by subscribing to specified topics on the cloud platform. It transmits its own data and status information, as well as that of the local data acquisition and control units it manages, to the cloud platform by publishing specific topics. When distinguishing between local data acquisition and control units, the local data acquisition and control unit number is used as the intermediate level of the topic.

[0094] Hierarchical structure explanation:

[0095] First level: Use the monitoring gateway UID to distinguish different monitoring gateways (electrolytic cells).

[0096] The second level: Local data acquisition and control unit numbers are used to distinguish different local data acquisition and control units. If no second level is set, the target object is a monitoring gateway.

[0097] The third level represents a business domain or system module. Examples include: "config", "sensor", "control", and "status".

[0098] The fourth level indicates a specific device type or functional group. For example, under "sensor" there is "temperature" (temperature sensor), and under "control" there is "enable" (enable / disable).

[0099] Fifth level: Represents the identifier of a specific acquisition and control channel or functional instance.

[0100] The list of topics and their descriptions are as follows:

[0101] 1. <gateway UID> / config / all

[0102] Purpose: Used by the cloud platform to send all configuration information to the monitoring gateway.

[0103] Message format: {"name":"xxx company, xxx workshop, xxx number",

[0104] "address":"1", "baudrate":"9600",

[0105] "devices":[

[0106] {"ID": "1", "UID":"xxxxxxxxxxxx", "address":"11", "type":"RS485},

[0107] {"ID": "2", "UID":"xxxxxxxxxxxx", "address":"12", "type":"RS485},

[0108] {"ID": "3", "UID":"xxxxxxxxxxxx", "address":"13", "type":"RS485}

[0109] (JOSON format, including the monitoring gateway name, communication address in the fieldbus, baud rate, and a list of local data acquisition and control units connected to the monitoring gateway)

[0110] Publishing permissions: The monitoring gateway and cloud platform have publishing permissions for the monitoring gateway communication module.

[0111] Subscription permissions: The cloud platform is responsible for monitoring the gateway communication module and the monitoring gateway has subscription permissions.

[0112] 2. <gateway UID> / config / name

[0113] Purpose: Used by the cloud platform to send name strings to the monitoring gateway.

[0114] Message format: {"name":"xxx company xxx workshop xxx number"} (JOSON format, including the monitoring gateway name)

[0115] Publishing permissions: Only the cloud platform's monitoring gateway communication module has publishing permissions.

[0116] Subscription permissions: Only the monitoring gateway has subscription permissions.

[0117] 3. <gateway UID> / config / address

[0118] Purpose: Used by the cloud platform to send address information from the online bus to the monitoring gateway.

[0119] Message format: {"address":"1"} (JOSON format, including the communication address of the monitoring gateway in the fieldbus)

[0120] Publishing permissions: Only the cloud platform's monitoring gateway communication module has publishing permissions.

[0121] Subscription permissions: Only the monitoring gateway has subscription permissions.

[0122] 4. <gateway UID> / config / baudrate

[0123] Purpose: Used by the cloud platform to send baud rate information from the online bus to the monitoring gateway.

[0124] Message format: {"baudrate":"9600"} (JOSON format, including the baud rate of the monitoring gateway in the fieldbus communication)

[0125] Publishing permissions: Only the cloud platform's monitoring gateway communication module has publishing permissions.

[0126] Subscription permissions: Only the monitoring gateway has subscription permissions.

[0127] 5. <gateway UID> / config / devices

[0128] Purpose: Used by the cloud platform to send the list of mounted local data acquisition and control units to the monitoring gateway.

[0129] Message format: {"devices":[

[0130] {"ID": "1", "UID":"xxxxxxxxxxxx", "address":"11", "type":"RS485},

[0131] {"ID": "2", "UID":"xxxxxxxxxxxx", "address":"12", "type":"RS485},

[0132] {"ID": "3", "UID":"xxxxxxxxxxxx", "address":"13", "type":"RS485}

[0133] (JOSON format, including a list of local data acquisition and control units mounted under the monitoring gateway)

[0134] Publishing permissions: Only the cloud platform's monitoring gateway communication module has publishing permissions.

[0135] Subscription permissions: Only the monitoring gateway has subscription permissions.

[0136] 6. <gateway UID> / status / connection

[0137] Purpose: Used to monitor the gateway and notify the cloud platform of the current connection status of the monitoring gateway.

[0138] Message format: {"status": "online|offline|drop"} (JOSON format, including the online, offline, and dropped status of the monitoring gateway)

[0139] Publishing permissions: The monitoring gateway has the permission to publish online and offline status. The message server has the permission to detect and publish offline status.

[0140] Subscription permissions: The cloud platform has subscription permissions for the monitoring gateway communication module.

[0141] 7. <gateway UID> / control / reset

[0142] Purpose: Used to monitor the gateway to notify the cloud platform of the local acquisition and control unit reset.

[0143] Message format: {"UID":"xxxxxxxxxxxx"} (JOSON format, including the target local acquisition and control unit UID)

[0144] Publishing permissions: Only the cloud platform's monitoring gateway communication module has publishing permissions.

[0145] Subscription permissions: Only the monitoring gateway has subscription permissions.

[0146] 8. <Gateway UID> / <Local Data Acquisition and Control Unit Number> / status / connection

[0147] Purpose: Used to monitor the gateway's notification to the cloud platform of the current connection status of the local data acquisition and control unit.

[0148] Message format: {"status": "online|offline "} (JOSON format, indicating whether the monitoring gateway is online or offline)

[0149] Publishing permissions: Only the monitoring gateway has publishing permissions.

[0150] Subscription permissions: Only the cloud platform's monitoring gateway communication module has subscription permissions.

[0151] 9. <Gateway UID> / <Local Data Acquisition and Control Unit Number> / status / mode

[0152] Purpose of the subject:

[0153] This is used to monitor the gateway and notify the cloud platform of the current operating mode of the local data acquisition and control unit.

[0154] This is used by the cloud platform to send the current operating mode of the local data acquisition and control unit to the monitoring gateway.

[0155] Message format: {"mode":"auto|manual_on|manual_off", "sender":"cloud|device"} (JOSON format, including the monitoring gateway's working mode and publisher type)

[0156] Publishing permissions: The monitoring gateway and cloud platform have publishing permissions for the monitoring gateway communication module.

[0157] Subscription permissions: The cloud platform is responsible for monitoring the gateway communication module and the monitoring gateway has subscription permissions.

[0158] 10. <Gateway UID> / <Local Data Acquisition and Control Unit Number> / status / enable

[0159] Purpose of the subject:

[0160] This is used to monitor the gateway and notify the cloud platform of the current enabled / disabled status of all acquisition and control channels of the local acquisition and control unit.

[0161] Used by the cloud platform to send the enable / disable status of all acquisition and control channels of the local acquisition and control unit to the monitoring gateway.

[0162] Message format: {"enable":" true, true, true, true, true, true, true, true","sender":"cloud|device"} (JOSON format, containing the enable / disable status of all acquisition and control channels of the monitoring gateway and the publisher type.)

[0163] Publishing permissions: The monitoring gateway and cloud platform have publishing permissions for the monitoring gateway communication module.

[0164] Subscription permissions: The cloud platform is responsible for monitoring the gateway communication module and the monitoring gateway has subscription permissions.

[0165] 11. <Gateway UID> / <Local Data Acquisition and Control Unit Number> / control / enable / <1-8>

[0166] Purpose: Used by the cloud platform to send the enable / disable status of a specific acquisition and control channel of the local acquisition and control unit to the monitoring gateway.

[0167] Message format: {"enable":"true|false"} (JOSON format, containing the enable / disable status of the acquisition and control channel)

[0168] Publishing permissions: Only the cloud platform's monitoring gateway communication module has publishing permissions.

[0169] Subscription permissions: Only the monitoring gateway has subscription permissions.

[0170] 12. <Gateway UID> / <Local Data Acquisition and Control Unit Number> / status / channel_mode

[0171] Purpose of the subject:

[0172] This is used to monitor the gateway and notify the cloud platform of the current working mode of all acquisition and control channels of the local acquisition and control unit.

[0173] This is used by the cloud platform to distribute the working modes of all acquisition and control channels of the local acquisition and control unit to the monitoring gateway.

[0174] Message format: {"mode":" auto, auto, auto, auto, auto, auto, auto, auto", "sender":"cloud|device"} (JOSON format, containing the working modes and publisher types of all acquisition and control channels of the monitoring gateway.)

[0175] Publishing permissions: The monitoring gateway and cloud platform have publishing permissions for the monitoring gateway communication module.

[0176] Subscription permissions: The cloud platform is responsible for monitoring the gateway communication module and the monitoring gateway has subscription permissions.

[0177] 13. <Gateway UID> / <Local Data Acquisition and Control Unit Number> / control / channel_mode / <1-8>

[0178] Purpose: Used by the cloud platform to issue the working mode of a specific acquisition and control channel of the local acquisition and control unit to the monitoring gateway.

[0179] Message format: {"mode":"auto|manual_on|manual_off"} (JOSON format, including the working mode of the data acquisition and control channel)

[0180] Publishing permissions: Only the cloud platform's monitoring gateway communication module has publishing permissions.

[0181] Subscription permissions: Only the monitoring gateway has subscription permissions.

[0182] 14. <Gateway UID> / <Local Data Acquisition and Control Unit Number> / config

[0183] Purpose of the subject:

[0184] This is used to monitor the gateway and notify the cloud platform of the current threshold configuration of all acquisition and control channels of the local acquisition and control unit.

[0185] Used by the cloud platform to send threshold configurations for all acquisition and control channels of the local acquisition and control unit to the monitoring gateway.

[0186] Message format: {"devices":[

[0187] {"ID":"1", "threshold":"199.9", "hysteresis":"10.1", "compensation":"5.1"},

[0188] {"ID":"2", "threshold":"199.9", "hysteresis":"10.1", "compensation":"5.1"},

[0189] {"ID":"3", "threshold":"199.9", "hysteresis":"10.1", "compensation":"5.1"},

[0190] {"ID":"4", "threshold":"199.9", "hysteresis":"10.1", "compensation":"5.1"},

[0191] {"ID":"5", "threshold":"199.9", "hysteresis":"10.1", "compensation":"5.1"},

[0192] {"ID":"6", "threshold":"199.9", "hysteresis":"10.1", "compensation":"5.1"},

[0193] {"ID":"7", "threshold":"199.9", "hysteresis":"10.1", "compensation":"5.1"},

[0194] {"ID":"8", "threshold":"199.9", "hysteresis":"10.1", "compensation":"5.1"}

[0195] ], "sender":"cloud|device"} (JOSON format, including hysteresis threshold, hysteresis value, compensation value and publisher type for all acquisition and control channels of the monitoring gateway)

[0196] Publishing permissions: The monitoring gateway and cloud platform have publishing permissions for the monitoring gateway communication module.

[0197] Subscription permissions: The cloud platform is responsible for monitoring the gateway communication module and the monitoring gateway has subscription permissions.

[0198] 15. <Gateway UID> / <Local Data Acquisition and Control Unit Number> / config / <1-8>

[0199] Purpose: Used to monitor the gateway to notify the cloud platform of the specific acquisition and control channel threshold configuration of the local acquisition and control unit.

[0200] Message format: { "threshold":"199.9", "hysteresis":"10.1", "compensation":"5.1"} (JOSON format, including the working mode of the data acquisition and control channel)

[0201] Publishing permissions: Only the cloud platform's monitoring gateway communication module has publishing permissions.

[0202] Subscription permissions: Only the monitoring gateway has subscription permissions.

[0203] 16. <Gateway UID> / <Local Data Acquisition and Control Unit Number> / sensor / temperature / <1-8>

[0204] Purpose: Used to monitor the gateway and notify the cloud platform of the current temperature value of the specific acquisition and control channel of the local acquisition and control unit.

[0205] Message format: { "value":"99.9", "errcode":"0"} (JOSON format, containing the temperature value and fault code of the data acquisition and control channel)

[0206] Publishing permissions: Only the monitoring gateway has publishing permissions.

[0207] Subscription permissions: Only the cloud platform's monitoring gateway communication module has subscription permissions.

[0208] 17.<Gateway UID> / <Local Data Acquisition and Control Unit Number> / radiator / output / <1-8>

[0209] Purpose: Used to monitor the gateway's notification to the cloud platform of the current output signals of specific acquisition and control channels of the local acquisition and control unit, the start / stop status of the heat dissipation module, and fault codes.

[0210] Message format: { "output":"on|off", "status":"start|stop", "errcode":"0"} (JOSON format, including the current output signal of the acquisition and control channel, the status of the heat dissipation module, and the fault code)

[0211] Publishing permissions: Only the monitoring gateway has publishing permissions.

[0212] Subscription permissions: Only the cloud platform's monitoring gateway communication module has subscription permissions.

[0213] Furthermore, in terms of hardware design, such as Figure 6As shown, each of the local data acquisition and control units includes a controller (MCU), a temperature measurement module circuit, a display module circuit, and a button module circuit. The controller is connected to the heat dissipation module, temperature measurement module circuit, display module circuit, and button module circuit. In this embodiment, the GD32G553 microcontroller is used as the core controller [180MHz clock speed, 244DMIPS computing power, state-of-the-art Cortex-M33 core, powerful peripheral support, and provides an NPU, especially powerful floating-point processing capabilities, with built-in hardware multipliers / dividers and a complete DSP instruction set and single-precision floating-point unit (FPU). It is also equipped with a new hardware trigonometric function accelerator (TMU), which can support vector, sine, cosine, exponential, square root, and common logarithmic mathematical trigonometric operations to reduce the burden of logical operations and improve processing efficiency, thereby promoting advanced computing applications centered on digital signal processing. Due to its superior performance in industrial real-time monitoring, it is widely used in high-speed AD acquisition, PWM, and other industrial applications. Together with other module circuits, they form the complete system of the local temperature measurement unit, which includes a main control section, an input section, and an output section. The controller of the main control section uses a GD32G553 microcontroller, which mainly utilizes its high-speed AD to acquire analog data, process it internally, and control the output section. The input section consists of two parts. The first part is the temperature measurement module circuit, which consists of a small signal processing circuit, a signal amplification circuit, a multi-channel circuit, and the temperature sensor. This module circuit amplifies the signal from the PT100 temperature sensor and supplies it to the controller (microcontroller) ADC for data processing. The second part is an independent button module circuit, which can switch modes and set the upper and lower limits of preset temperature thresholds. The display module circuit (output section) includes two parts: a display screen module and an LED display module. The display screen module can display the temperature, upper and lower limit thresholds, and mode measured by the current temperature measuring module circuit. When the temperature measured by the temperature measuring module circuit is lower than the set lower limit, the green LED of the LED display module lights up; when the temperature measured by the temperature measuring module circuit is higher than the upper limit temperature, the red LED of the LED display module lights up.

[0214] Specific circuit design

[0215] 1. Main control circuit

[0216] The GD32G553 is used to communicate with peripherals, process data, and control the entire system.

[0217] 2. PT100 constant current source circuit

[0218] The PT100 measurement circuit offers two methods: bridge and constant current measurement. Figure 7As shown, this embodiment uses a constant current source for measurement. When using a constant current source, the current magnitude needs to be considered. If the current is too large, due to the self-heating effect of the PT100, 1mW will cause a temperature change of approximately 0.02–0.75℃. If the current is too small, the signal generated by the PT100 is easily affected by external noise. Therefore, a value of 0.5–2 mA is generally suitable. In this design, a 1mA constant current source is selected. This constant current source uses a voltage-controlled constant current source with negative feedback, composed of an operational amplifier and a transistor. The entire constant current source circuit consists of an operational amplifier GS8552, a TL431 2.5V reference voltage source, resistors, and a 9012 PNP transistor. The TL431 provides a 2.5V voltage reference to the non-inverting input of the GS8552. According to the "virtual short" of the operational amplifier, the inverting input voltage is also 2.5V. The current flowing through R2 is 1mA. The Ib of the transistor flowing through the composite transistor is very small; it can be approximated that all 1mA flows into the PT100.

[0219] 3. PT100 signal amplification circuit

[0220] like Figure 8 As shown, the operational amplifier selection for the Pt100 signal amplification circuit considers the following: The Vref of the internal ADC of the GD32G553 is 3.3V, the output voltage of the entire operational amplifier circuit must be less than 3.3V, and the operating voltage VDD of the operational amplifier must be greater than 3.3V. Secondly, considering the PT100 DC system, the GBW of the operational amplifier can generally be selected. Given the use of operational amplifiers to form a differential circuit, the op-amp needs to have excellent common-mode rejection ratio (CMRR). Vos and temperature drift should also be as small as possible. In summary, considering the design does not rely on a digitally controlled dual power supply and a downstream voltage follower protection circuit, the domestic GS8552 is selected as the operational amplifier. This op-amp supports single-supply operation, with a single-supply range of +1.8V to +5.5V, meeting the design requirements of an output voltage within 3.3V and supporting single-supply operation. Its Vos is only 30ua and its temperature drift is only 0.01ua / ℃. This op-amp is rail-to-rail input / output, meeting the design requirements of the downstream voltage follower protection circuit.

[0221] In the differential amplifier circuit, considering the resistance of the PT100 at 100℃ is approximately 139Ω and the current flowing through it is 1mA, the resulting voltage is approximately 0.139V. Taking into account the reference voltage of the downstream ADC at 3.3V, G = 3.3V / 0.139V ≈ 23.74. Therefore, the amplification factor cannot exceed 23.74 times. To maximize the measurement range, a amplification factor of 21 times is chosen. Without considering the voltage drop caused by subtracting line resistance, the output voltage of the operational amplifier is V. out = 0.139 * 21 = 2.919V

[0222] 4. System Power Supply Design

[0223] The power supply design uses a 12V power supply that is stepped down by an 1117-5 chip to power the op-amp.

[0224] 5. System peripheral circuit design

[0225] like Figures 9-12 As shown, the peripheral circuits of this system mainly include the JLX12864 display circuit (i.e., the display module), the BH45B1225 circuit (the BH45B1225 is a multi-channel 24-bit Delta Sigma A / D converter with a built-in programmable gain amplifier, specifically designed for differential interface applications with analog signals), the sound and light alarm circuit (i.e., the LED display module), and the KEY circuit (i.e., the button module circuit). The BH45B1225 uses the I2C protocol and requires two pull-up resistors at SCL and SDA.

[0226] PTC thermocouple design

[0227] The connection between the PT100 temperature sensor and the field instrument is relatively long, and the resistance of the connecting wires will introduce measurement errors. Therefore, a three-wire system is often used in industry to eliminate the errors introduced by the wires. The principle of the three-wire system is as follows: Figure 13 As shown. The resistance of the wires during measurement is rL1, rL2, and rL3. The three wires are of the same specification and length. Therefore, RT is the resistance of PT100. The measurement circuit at the measurement terminals U1 and U2 adopts a high-impedance input circuit. To measure the resistance of RT, a constant current I is added to the U1 terminal. Then the voltage U1 is: U1 = I × (rL1 + RT + rL2) = I × (RT + 2rL); Since the U2 measurement terminal is a high-impedance input terminal, no current flows through the wire, so: U2 = I × rL3 = I × rL; Subtracting twice the amount of (2) from (1) gives: U1 - 2U2 = I × (RT + 2rL) - 2 × I × rL = I × RL = Uab; Therefore, RT = (U1 - 2U2) / I. In the formula, RT has eliminated the influence of the wire resistance rL on the measurement. It can be seen that the measurement only requires providing a constant current I and measuring U1-2U2.

[0228] Based on the above analysis of the 3-wire principle, the 3-wire RTD measurement circuit designed in this embodiment is as follows: Figure 14As shown, the circuit consists of two parts: a constant current source circuit and a differential amplifier circuit. The constant current source circuit mainly comprises a voltage reference chip LM358-2.5, a high-precision operational amplifier KTA2333, and transistors Q1 and Q2. The constant current source circuit uses the integrated voltage reference chip LM385-2.5 to provide a reference voltage Ud = 2.5V. Therefore, the voltage at pin ③ of the operational amplifier's non-inverting input is 5V-Ud. Based on the virtual short characteristic of the operational amplifier, the voltage at pin ② of the inverting input U1.1 is also 5V-Ud. That is, the emitter voltage of transistor Q1 is 5V-Ud. Since one end of the current sampling resistor R2 is 5V and the other end is connected to the emitter of Q1, the actual voltage applied across R2 is:

[0229] 5V - (5V - Ud) = Ud.

[0230] Therefore, the current flowing through R2 is: I = Ud / R1 = 2.5V / 2.7K ≈ 0.926mA.

[0231] According to the virtual open circuit characteristic of the op-amp, no current flows between R2 and pin ② of the inverting terminal of U1.1. Therefore, all the current in resistor R2 flows into the emitter of transistor Q1. The IC1 of the composite transistors Q1 and Q2 is IE1 - IB2, where IC1 = β1β2IB2. Since the β values ​​of Q1 and Q2 are generally above 100, IC1 > 10000 × IB2. Therefore, IC1 can be approximated as IE1 with an error of less than 0.01%, which can be ignored. Thus, the collector current of transistor Q1 is the emitter current. Furthermore, the influence of the +5V power supply voltage is eliminated during the operation. The error is only related to resistor R2 and the voltage reference U2. Therefore, resistor R2 should be a metal film resistor with a small temperature drift. The differential amplifier circuit mainly consists of operational amplifiers U1 and U2 and resistors R3, R5~R9. Its input-output transfer function is as follows:

[0232] Uo = (R9+R8) / R9 * [ (R6 + R7) / (R3 + R5) * R5 / R6 * U1 - R7 / R6*U2 ] =11 * (U1 - 2U2)

[0233] RT = (U1-2U2) / I, I = Ud / R2

[0234] Therefore, RT = Uo / 11 / I = (Uo * 2700 ) / (11 * 2.5)

[0235] The signal, after differential amplification by operational amplifier U1.2, is low-pass filtered by R10 and C4 before being sent to the AD converter for digital measurement. The temperature value is obtained by referring to the PT100 calibration table based on the measured RT value and performing interpolation. To improve measurement accuracy, the commonly used KTA2333 low-noise, low-temperature-drift precision operational amplifier is selected in the circuit. Its input offset voltage is less than 10μV, input bias current is ±100pA, input offset voltage is ±120pV, and offset voltage drift is only 0.05μV / ℃. This embodiment includes an ADC selection mechanism, allowing selection between an external and internal ADC via a jumper. Given that the MCU's ADC reference selection is 3.3V DC-DC, an external ADC is recommended at a transmission rate of 10sps with an effective bit depth of 21.5 bits. To ensure accuracy, the resistors related to the operational amplifier should ideally be 0.1% precision resistors.

[0236] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. Any simple equivalent changes and modifications made in accordance with the scope of the patent application and the description of the invention shall still fall within the scope of the patent of the present invention.

Claims

1. An aluminium electrolysis cell shell temperature monitoring system characterised in that, It comprises a monitoring client, a tank shell temperature monitoring cloud platform and a plurality of on-site control units, each of which comprises a plurality of temperature sensors and a plurality of heat dissipation modules; each of the on-site control units acquires temperature data of key points of the electrolytic tank shell in real time through the temperature sensors, accurately controls the operation of the heat dissipation modules according to a preset temperature threshold, and monitors the state of the heat dissipation modules; all the on-site control units receive control commands of a monitoring gateway through a field bus, and transmit temperature information acquired by the temperature sensors and state information of the heat dissipation modules to the monitoring gateway; the monitoring gateway polls the temperature and state information acquired by the on-site control units, transmits the data to the tank shell temperature monitoring cloud platform through a network transmission device, and forwards control commands of the tank shell temperature monitoring cloud platform to the on-site control units; the tank shell temperature monitoring cloud platform is data-connected with the monitoring client; each of the on-site control units comprises a controller, a temperature measurement module circuit, a display module circuit and a key module circuit, and the controller is data-connected with the heat dissipation modules, the temperature measurement module circuit, the display module circuit and the key module circuit.

2. An aluminium reduction cell shell temperature monitoring system according to claim 1, characterised in that, The temperature sensor adopts a PT100 temperature sensor, which has a measurement range of -55℃~600℃ and an error of ±0.1℃.

3. An aluminium reduction cell shell temperature monitoring system according to claim 1, characterised in that, RS485 / CAN bus is used as the field bus to form a communication network of the monitoring gateway and the on-site control units of a designated electrolytic tank, and ModBus-RTU standard protocol is used to interact data.

4. An aluminum cell shell temperature monitoring system as claimed in claim 1 wherein, The monitoring gateway and the tank shell temperature monitoring cloud platform use MQTT protocol to interact data.

5. An aluminum cell shell temperature monitoring system as claimed in claim 1 wherein, A GD32G553 single-chip microcomputer is selected as the controller.

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