Data acquisition and control system and method based on RT-Thread

Abstract

The invention discloses a data acquisition and control system based on RT-Thread and a method thereof. The system comprises a hardware system and a software system, the method comprises the following steps: deploying an RT-Thread operating system on an MCU (Microprogrammed Control Unit); a hardware interrupt triggering mode is used on the MCU to process key tasks with high real-time performance; a complex application function is realized by utilizing a task scheduling mechanism of the RT-Thread, and the development process is accelerated by using abundant intermediate layer components and software packages of the RT-Thread. According to the method, the RT-Thread operating system is deployed in the MCU system with limited resources, so that the real-time performance of high-priority key tasks can still be ensured on the premise that the hardware cost is not increased, meanwhile, rich and complex system application functions can be realized, the intelligent level of a product is improved, and the competitiveness of the product is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power secondary equipment data acquisition control, and particularly relates to a data acquisition and control system based on RT-Thread and a method thereof. BACKGROUND

[0002] In the field of power system distribution automation, intelligent distribution terminal devices need to collect and process analog and switching signals of primary electrical equipment, and issue corresponding control signals to control the operation of electrical equipment. With the improvement of the performance of microcontrollers (MCU), their hardware resources are becoming more abundant and their operation speed is becoming faster. Many low-cost intelligent measurement and control devices use high-performance MCUs as main controllers. Since high real-time performance is required from input signal collection to output control signal, these devices usually run in a bare machine mode, that is, the application program directly operates hardware resources without using an operating system (OS).

[0003] To achieve high real-time performance, bare machine programming generally uses a mode of hardware interrupt triggering + main loop query. Key tasks with high real-time requirements are triggered by hardware interrupts, and high-priority tasks are processed in the interrupt service program (ISR). In the main loop, various conditions and events are continuously queried, and each low-priority and background task is processed in a fixed order. This mode can process key tasks in time and has high real-time performance, so it has been widely used.

[0004] With the rapid development of the Internet of Things and artificial intelligence, the intelligent level of various terminal devices needs to be improved. However, bare machine programming cannot implement complex system functions such as network services, file management, graphical interfaces, and log reporting. One reason is that the implementation of these tasks is complex, and the other reason is that running these complex and time-consuming tasks in the main loop will cause the system to freeze or run abnormally. The disadvantages of the bare machine system are obvious. The low-priority tasks executed in the main loop will affect each other. When one task is being executed, even if the condition of another task has been met, it cannot be executed until all the tasks in front of it have been executed. If the current task is a time-consuming task or the current task is waiting for an event for a long time, other tasks cannot be executed in time, resulting in low CPU utilization. Therefore, the bare machine system can only implement some simple system functions, otherwise it will cause the system to freeze. In addition, the bare machine system also has the disadvantages of poor portability, poor configurability, and poor debuggability.

[0005] In order to provide rich and complex system functions while ensuring high real-time, the existing scheme generally adopts a dual-CPU (core) architecture, one CPU (core) is responsible for system running management, referred to as management CPU (core), and the other CPU (core) is responsible for real-time task processing, referred to as real-time CPU (core). The management CPU (core) usually runs the Linux or VxWorks operating system, which can provide complex system functions such as network service, file system, running management and log reporting, and the real-time CPU (core) adopts a bare machine running mode of hardware interrupt triggering + main loop query, processes high real-time tasks in the interrupt service program, and processes simple non-real-time tasks in the main loop.

[0006] The dual-CPU (core) system has high hardware cost and complex architecture design. The management CPU (core) needs a high-end processor and a large amount of hardware resources to run the Linux or VxWorks operating system. Moreover, complex data interaction, resource management and coordination mechanism between the two CPUs (cores) are needed for stable operation. For widely distributed and large amount of power distribution automation terminal devices, this scheme is obviously too high in cost.

[0007] Therefore, in view of the above problems, a single-core data acquisition and control method based on RT-Thread is proposed. SUMMARY

[0008] The purpose of the present application is to provide a data acquisition and control system and method based on RT-Thread, which can process high real-time key tasks using hardware interrupt triggering mode and realize complex application functions using the task scheduling mechanism of the RT-Thread real-time operating system kernel.

[0009] Technical scheme: The data acquisition and control system based on RT-Thread comprises a hardware system and a software system, wherein the hardware system comprises an MCU processor, a switching value acquisition module, an analog value acquisition module, a control output module, a communication interface module, a calendar clock module, a man-machine interaction module, an extended memory module and a power management module; the software system comprises an MCU hardware abstraction layer, an RT-Thread operating system layer and an application layer from bottom to top; wherein the MCU hardware abstraction layer provides interface functions for accessing the MCU bottom hardware; the RT-Thread operating system layer mainly comprises a kernel, a device driver, components and software packages, which realize scheduling switching and thread communication of multi-thread tasks, registration and access of hardware devices, various intermediate layer components and software packages.

[0010] Further, the analog quantity acquisition module comprises an alternating current analog quantity input loop, a direct current analog quantity input loop and an AD conversion chip; and is used for acquiring the on-off position of a primary switch, a switch energy storage signal and an operating power state quantity.

[0011] Further, the control output module comprises an optoelectronic isolation, a switching quantity signal output and a relay loop, and is used for controlling the on-off of the primary switch.

[0012] Further, the communication interface module comprises a 2-way Ethernet interface and a 3-way serial port, supports the device to communicate with a superior master station or a local device through a wired or wireless network, and provides a local maintenance interface.

[0013] Further, the extended memory module comprises an external SDRAM and an SPI FLASH memory, and is used for storing running data and a recording file; the MCU accesses the SDRAM through an EXMC interface and accesses the FLASH memory through an SPI interface.

[0014] The RT-Thread-based data acquisition and control method comprises the following steps:

[0015] (1) deploying an RT-Thread operating system on an MCU;

[0016] (2) using a hardware interrupt trigger mode to process a high real-time key task on the MCU;

[0017] (3) using a task scheduling mechanism of the RT-Thread to realize a complex application function, and using rich intermediate layer components and software packages of the RT-Thread to speed up a development process.

[0018] Further, the step (1) comprises:

[0019] (1.1) selecting an existing BSP (Board Support Package) close to the MCU model used as a template, and creating an RT-Thread project;

[0020] (1.2) editing a Kconfig file to adapt to the MCU hardware configuration, including specifying a chip model and enabling peripherals;

[0021] (1.3) editing a link script file, adjusting the start address and size of a Flash and a RAM according to the MCU model, configuring program space and data space, and dividing stack space;

[0022] (1.4) Modify the interrupt vector table and startup code in startup*.s according to MCU model; Modify the global interrupt on / off function, thread context switch function in context*.s file according to MCU architecture, implement PendSV interrupt handling function, complete the actual work of thread switching;

[0023] (1.5) Configure the clock tick of SysTick system clock according to system needs, implement SysTick interrupt handling function, ensure that the rt_tick_increase() function is periodically called in the interrupt of clock tick;

[0024] (1.6) Edit board.c to implement board-level initialization, including initializing interrupt vector table, system clock, stack pointer and console serial port, enabling interrupt nesting.

[0025] (1.7) Write drivers for various devices based on the RT-Thread device driver framework, such as GPIO, UART, I2C, SPI, and ENET devices, and use the INIT_BOARD_EXPORT macro definition to add device initialization functions to the automatic initialization list, which will be automatically called during system initialization to register the device with the kernel;

[0026] (1.8) Enable relevant middleware components in menuconfig as needed, such as 1wIP protocol stack, file system, ulog component, the initialization functions of these components will be automatically called during system initialization.

[0027] Further, the step (2) comprises:

[0028] (2.1) After system initialization, open the interrupt trigger device in the main thread, set the interrupt trigger condition and priority;

[0029] (2.2) Write the processing function of the critical application task, and set it as the callback function of the interrupt service program, start the interrupt trigger device;

[0030] (2.3) Through the above steps, when the interrupt is triggered, the function of the critical task will be called in the interrupt service program, and its priority is higher than that of other interrupt tasks, and higher than that of all thread tasks, under the premise of supporting interrupt nesting in MCU, it is ensured that the high real-time critical task can be executed in time.

[0031] Further, the step (3) comprises but is not limited to:

[0032] Use 1wIP component to deploy 1wIP lightweight network protocol stack on MCU, implement TCP, UDP, HTTP client / server network application;

[0033] Use the file system component to mount the file system on the MCU chip or in the external FLASH memory to facilitate file operations and management;

[0034] Implement MQTT, CoAP, and Modbus communication protocols using communication components;

[0035] Develop graphical user interfaces quickly using LVGL components.

[0036] Furthermore, the triggering conditions for step (2.1) include rising edge triggering, falling edge triggering, or timed triggering.

[0037] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: The present invention deploys the RT-Thread operating system in a resource-constrained MCU system, which can still ensure the real-time performance of high-priority critical tasks without increasing hardware costs, while also realizing rich and complex system application functions, improving the intelligence level of the product and enhancing the product's competitiveness. Attached Figure Description

[0038] Figure 1 This is a hardware system block diagram of the device of the present invention;

[0039] Figure 2 This is a software system block diagram of the device of the present invention;

[0040] Figure 3 This is a hardware block diagram of the DTU device of the present invention;

[0041] Figure 4 This is a block diagram of the software composition of the DTU device of the present invention. Detailed Implementation

[0042] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0043] like Figure 1 The diagram shown is a hardware system block diagram of this device, which mainly includes an MCU processor, a digital signal acquisition module, an analog signal acquisition module, a control output module, a communication interface module, a calendar clock module, a human-machine interaction module, an extended memory module, and a power management module.

[0044] like Figure 2The software system block diagram of the device is shown, including MCU hardware abstract layer (HAL, Hardware Abstract Layer), RT-Thread operating system layer and application layer from bottom to top. Among them, the MCU hardware abstract layer provides interface functions for accessing the underlying hardware of the MCU; the RT-Thread operating system layer mainly consists of three parts of kernel, device driver, component and software package, which respectively realize scheduling switching and inter-thread communication of multi-thread tasks, registration and access of hardware devices, various intermediate layer components and software packages.

[0045] The application can be used for a distribution terminal unit (DTU) of power system distribution automation station, which is a distribution automation terminal device integrating functions of telemetry, remote signaling, remote control, protection and communication. The DTU is generally installed at conventional switching station, outdoor small switching station, ring network cabinet, small substation, box-type substation and the like, completes collection and calculation of position signal, voltage, current, active power, reactive power, power factor, electric energy and the like of switching device, performs opening and closing operation on the switch, realizes fault identification, isolation of feeder switch and recovery of power supply in non-fault section, and part of the DTU also has the functions of protection and automatic input of standby power.

[0046] The device of the application adopts a 32-bit high-performance low-power MCU of GD32 series, which has floating point operation function, low interrupt delay time and low-cost debugging characteristics, supports a powerful and expandable instruction set, including general data processing I / O control task, enhanced data processing bit domain operation, DSP (digital signal processing) and floating point operation instruction.

[0047] As Figure 3 The hardware composition block diagram of the device is shown, mainly including MCU processor, analog quantity acquisition module, switching quantity acquisition module, control output module, communication module, calendar clock module, man-machine interaction module, extended memory module, power management module and the like. Among them:

[0048] The MCU processor is a domestic GD32 high-performance low-power MCU controller.

[0049] The analog quantity acquisition module includes AC analog quantity input loop, DC analog quantity input loop and AD conversion chip. It is used for collecting voltage and current AC signals of primary switch and DC signals such as standby battery voltage and environmental temperature. The MCU accesses the AD conversion chip through the EXMC parallel interface.

[0050] The switching quantity acquisition module includes switching quantity signal input and photoelectric isolation loop, which is used for collecting the split and combined position of primary switch, switching energy storage signal, operating power and the like. The MCU collects the switching quantity through the GPIO pin.

[0051] The control output module includes photoelectric isolation, switch signal output and relay loop for controlling the opening and closing of primary switches. The MCU outputs control signals through GPIO pins.

[0052] The communication interface module includes 2-way Ethernet interface and 3-way serial port, supporting the device to communicate with the upper master station or local devices through wired or wireless network, and providing a local maintenance interface.

[0053] The calendar clock module includes RTC chip and high-precision temperature-compensated crystal oscillator for providing accurate and reliable system time to the MCU. The MCU accesses the RTC chip through I2C interface.

[0054] The human-computer interaction module includes keys, LED indicator lights and LCD liquid crystal module for viewing device running status, modifying set values and configuring running modes, etc. The MCU accesses the LCD liquid crystal module through EXMC interface, and accesses the keys and LED indicator lights through GPIO interface.

[0055] The extended memory module includes external SDRAM and SPI FLASH memory for storing running data, recording files, etc. The MCU accesses the SDRAM through EXMC interface, and accesses the FLASH memory through SPI interface.

[0056] The power management module is responsible for converting external power into weak power sources such as 5V, 3.3V and 1.8V used by the MCU system, and providing power-on reset, low voltage alarm and surge voltage and current protection functions.

[0057] As shown in Figure 4 The software composition block diagram of the device is shown in FIG. 1. The lowest layer is the MCU hardware abstraction layer, which provides interface functions for accessing the underlying hardware of the MCU, including GPIO, SPI, I2C, UART, EXMC and ENET, etc. The middle layer is the RT-Thread operating system, which can be roughly divided into kernel layer, device driver layer and component and software package layer. Among them, the kernel layer mainly includes real-time scheduler, software timer based on clock ticks, and kernel objects such as semaphores, mutexes and message queues for inter-thread communication, mainly implementing multi-task scheduling switching, inter-thread communication and memory management, etc.; the device driver layer is a device driver program written based on the RT-Thread device driver framework, providing registration and access interface functions of each hardware device of the MCU; the component and software package layer provides various intermediate layer components and software packages adapted to RT-Thread, including 1wIP component, file system component, MQTT protocol software package and LVGL graphics library, etc. The uppermost layer is the application layer, including interrupt tasks with high real-time requirements and thread tasks with low real-time requirements.

[0058] 1、The embodiment of the present application needs to deploy RT-Thread operating system on GD32 MCU, and the specific steps are as follows:

[0059] Select the GD32F450Z BSP project as a template to create a new RT-Thread project.

[0060] Edit the Kconfig file to adapt to the MCU hardware configuration, specify the chip model, and enable peripherals such as GPIO, UART, SPI, I2C, HWTIMER, ENET and EXMC.

[0061] Edit the link script file gd32_rom.1d, adjust the start address and size of Flash and RAM according to the GD32 MCU model, configure the program space, data space, and divide the stack space.

[0062] Since the GD32 MCU architecture is the same, the interrupt vector table and startup code in the startup*.s file do not need to be modified, and the global interrupt on / off function, thread context switching function, and PendSV interrupt handling function in the context*.s file do not need to be modified.

[0063] Configure the clock tick of the SysTick system clock to be 1000Hz, i.e. the period is 1ms.

[0064] The SysTick interrupt handling function has been implemented in the GD32F450Z BSP template and does not need to be modified.

[0065] Edit the board.c board-level initialization code, only the system clock needs to be initialized according to the MCU frequency, and other modifications are not required.

[0066] Write the drivers of various devices based on the RT-Thread device driver framework, including GPIO, UART, I2C, SPI, HWTIMER, EXMC and ENET devices, and use the INIT BOARD EXPORT macro definition to add the device initialization function to the automatic initialization list, which will be automatically called during system initialization to register the device with the kernel.

[0067] Enable the relevant intermediate layer components and software packages in menuconfig, mainly including MSH components, SAL socket abstraction layer components, 1wIP protocol stack components, MQTT software packages, DFS virtual file system components, FLASH abstraction layer components, littleFS software packages, ULOG log components, etc. The initialization functions of these components will be automatically called during system initialization.

[0068] Through the above steps, the RT-Thread operating system can be successfully deployed on the GD32 MCU.

[0069] 2、The implementation of the application also needs to use the hardware interrupt trigger mode to process the high real-time key task on the GD32 MCU, and the hardware timer (HWTIMER) period interrupt is used in the equipment to process the high real-time key task, and the specific steps are as follows:

[0070] After the system initialization is completed and the main thread is entered, the HWTIMER1 equipment is opened, and the working frequency, interrupt period and interrupt priority thereof are set. The interrupt period can be less than 1ms of the system clock beat, and the equipment adopts 500us. The interrupt priority can be the highest priority allowed to be used by the system, and the equipment adopts 0 (the smaller the number is, the higher the priority is).

[0071] The processing function of the key application task is written, and the function is set as the callback function of the HWTIMER1 period interrupt task. The interrupt task cannot occupy too much CPU time, otherwise the operating system running efficiency will be affected. The task content mainly includes:

[0072] (1) On-off signal acquisition: the on-off position of a switch, the switch energy storage signal, the backup battery state and other state quantity acquisition.

[0073] (2) Analog signal acquisition: synchronous acquisition of multiple channels of alternating current voltage and current in the running of a switch.

[0074] (3) AC electrical quantity calculation: real-time calculation of active power, reactive power, power factor, AC frequency and other electrical quantities.

[0075] (4) Fault analysis and processing: real-time analysis of sampled current and voltage, judgment of fault nature (transient or permanent fault), fault type (ground fault, phase-to-phase fault or broken line, etc.), and corresponding processing (immediate trip, delay trip or report alarm).

[0076] The HWTIMER1 is set to the period interrupt mode, and the HWTIMER1 is started.

[0077] Through the above steps, the key application task function will be called periodically in the HWTIMER1 interrupt, and the priority is higher than that of other interrupt tasks, and is higher than that of all thread tasks. Under the premise that the GD32 MCU supports interrupt nesting, the high real-time key task is accurately and periodically executed.

[0078] 3、The application utilizes the task scheduling mechanism of RT-Thread to realize complex application functions, and uses the rich intermediate layer components and software packages of RT-Thread to speed up the development process and improve the development efficiency.

[0079] In this DTU device, the littleFS file system is deployed in the MCU's off-chip SPI FLASH using the DFS virtual file system component, FLASH abstraction layer component, and littleFS software package. This file system is used for the storage and management of configuration files, setting files, waveform recording files, and log files.

[0080] A lightweight TCP / IP protocol stack, 1wIP, was deployed in the MCU system using SAL socket abstraction layer components, network device components, and 1wIP components. Based on this, communication between the terminal devices and the power distribution master station was implemented using MQTT and CoAP protocol packages.

[0081] Beautiful graphical user interfaces were quickly developed using the LVGL lightweight general-purpose graphics library package.

[0082] Other application tasks in this DTU device that do not have particularly high real-time requirements are implemented using threads. Different thread priorities and time slices are set according to the task's real-time requirements and execution time. Utilizing the RT-Thread kernel's priority-based preemptive scheduling and time-slice-based round-robin scheduling algorithms, the CPU efficiently switches between tasks, ensuring the real-time execution of each task. These tasks, ordered from highest to lowest priority, mainly include:

[0083] Remote control command reception and processing: Receives remote control commands from the master station, performs opening / closing operations on primary switches, isolates faulty areas, and restores power supply to non-faulty areas.

[0084] Remote signaling data transmission: The status quantities such as switch position, switch energy storage and pressure interlock are sent to the master station, and priority is given to sending when the status changes.

[0085] Telemetry data transmission: AC and DC measurement data are transmitted to the master station on demand or periodically.

[0086] Fault recording: Starts when a fault occurs, records the voltage and current for a period of time before and after the fault, and saves them as a file in COMTRADE format.

[0087] Human-computer interaction: Detect buttons, update the graphical interface and LED indicators.

[0088] System time synchronization: Receives SNTP network time synchronization information from GPS or the master station and updates the system time.

[0089] Fixed value management: uploading, downloading, and modifying fixed values, and maintaining fixed value files.

[0090] Log management: Generation and rolling updates of operation logs, exception logs, and self-test log files.

[0091] Other tasks: including DC analog acquisition, backup power management and device self-checking / self-recovery functions, etc.

Claims

1. An RT-Thread-based data acquisition and control system, characterized in that, The system comprises a hardware system and a software system, the hardware system comprises an MCU processor, a switching quantity acquisition module, an analog quantity acquisition module, a control output module, a communication interface module, a calendar clock module, a man-machine interaction module, an extended memory module and a power management module; the software system comprises from bottom to top an MCU hardware abstraction layer, an RT-Thread operating system layer and an application layer; wherein the MCU hardware abstraction layer provides interface functions for accessing the MCU bottom hardware; the RT-Thread operating system layer mainly comprises a kernel, a device driver, a component and a software package, and realizes scheduling switching and inter-thread communication of multi-thread tasks, registration and access of hardware devices, various intermediate layer components and software packages.

2. The RT-Thread-based data acquisition and control system according to claim 1, characterized in that, The analog quantity acquisition module comprises an AC analog quantity input loop, a DC analog quantity input loop and an AD conversion chip; and is used for acquiring the on-off position of a primary switch, a switching energy storage signal and an operating power state quantity.

3. The RT-Thread based data acquisition and control system of claim 1, wherein, The control output module comprises an optoelectronic isolation, a switching quantity signal output and a relay loop, and is used for controlling the on-off of the primary switch.

4. The RT-Thread based data acquisition and control system of claim 1, wherein, The communication interface module comprises a 2-way Ethernet interface and a 3-way serial port, supports the device to communicate with a superior master station or a local device through a wired or wireless network, and provides a local maintenance interface.

5. The RT-Thread based data acquisition and control system of claim 1, wherein, The extended memory module comprises an external SDRAM and an SPI FLASH memory, and is used for storing running data and a recording file; the MCU accesses the SDRAM through an EXMC interface and accesses the FLASH memory through an SPI interface.

6. A data acquisition and control method based on RT-Thread, characterized in that, The method comprises the following steps: (1) deploying an RT-Thread operating system on the MCU; (2) using a hardware interrupt trigger mode to process high real-time key tasks on the MCU; (3) using the task scheduling mechanism of the RT-Thread to realize complex application functions, and using the rich intermediate layer components and software packages of the RT-Thread to speed up the development process.

7. The RT-Thread-based data acquisition and control method according to claim 6, characterized in that, The step (1) comprises: (1.1) selecting an existing BSP board support package similar to the used MCU model as a template to create an RT-Thread project; (1.2) editing a Kconfig file to adapt to the MCU hardware configuration, including specifying the chip model and enabling the peripheral; (1.3) editing a link script file, adjusting the start address and size of the Flash and RAM according to the MCU model, configuring the program space and data space, and dividing the stack space; (1.4) modifying the interrupt vector table and startup code in the startup_*.s file according to the MCU model, modifying the global interrupt on / off function and thread context switching function in the context_*.s file according to the MCU architecture, realizing the PendSV interrupt processing function, and completing the actual work of thread switching; (1.5) configuring the clock tick of the SysTick system clock according to the system requirement, realizing the SysTick interrupt processing function, and ensuring that the rt_tick_increase() function is periodically called in the clock tick interrupt. (1.6) Edit the board.c implementation of the board-level initialization, including initializing the interrupt vector table, system clock, stack pointer, and console serial port, enabling interrupt nesting. (1.7) Write drivers for various devices based on the RT-Thread device driver framework, such as GPIO, UART, I2C, SPI, and ENET devices, and use the INIT_BOARD_EXPORT macro to add device initialization functions to the automatic initialization list, which will be automatically called during system initialization to register the device with the kernel. (1.8) Enable relevant middleware components in menuconfig as needed, such as the 1wIP protocol stack, file system, and ulog components, whose initialization functions will be automatically called during system initialization.

8. The RT-Thread-based data acquisition and control method according to claim 6, characterized in that, The step (2) comprises: (2.1) After system initialization, open the interrupt trigger device in the main thread, set the interrupt trigger condition and priority; (2.2) Write the processing function of the critical application task and set it as the callback function of the interrupt service program, and start the interrupt trigger device; (2.3) Through the above steps, when the interrupt is triggered, the function of the critical task will be called in the interrupt service program, and its priority is higher than that of other interrupt tasks, and higher than that of all thread tasks, which ensures that the high real-time critical task can be executed in time under the premise of supporting interrupt nesting in MCU.

9. The RT-Thread-based data acquisition and control method according to claim 6, characterized in that, The step (3) includes but is not limited to: Use the 1wIP component to deploy the 1wIP lightweight network protocol stack on the MCU, implement TCP, UDP, HTTP client / server network applications; Use the file system component to mount the file system on the MCU or off-chip FLASH, facilitating file operations and management; Use the communication component to implement MQTT, CoAP, Modbus communication protocols; Use the LVGL component to quickly develop a graphical user interface.

10. The RT-Thread-based data acquisition and control method according to claim 8, characterized in that, The trigger condition of step (2.1) includes rising edge trigger, falling edge trigger, or timing trigger.

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