ARM-based Linux Computer with Qt to Develop Automated Control Panel

What is Qt?

Qt is a cross-platform C++ application development framework developed by Qt Company, widely used for creating graphical user interfaces (GUIs) as well as non-GUI applications. It is particularly suitable for developing embedded systems, desktop applications, and mobile applications. Below are the main features of Qt:

1. Cross-Platform Capability:
   • Qt supports operation across multiple operating systems (e.g., Windows, Linux, macOS, embedded Linux, Android, iOS, etc.), allowing code to be written once and deployed on different platforms.
   • In embedded systems, Qt is often paired with ARM processors to develop efficient HMIs (Human-Machine Interfaces).
2. Main Components:
   • Qt Widgets: Used for developing traditional desktop-style GUIs, suitable for complex interfaces.
   • Qt Quick: Based on QML (a declarative language), it is used to develop lightweight, smooth touch interfaces, particularly suited for embedded devices.
   • Qt Charts: Provides data visualization features, such as drawing line charts, bar charts, etc.
   • Communication Modules: Supports serial communication and network protocols (e.g., TCP/IP, MQTT), facilitating interaction with hardware or cloud systems.
3. Applications in Automation Control Panels:
   • Combined with ARM-based Linux Computer, Qt can be used to develop intuitive control panel interfaces, supporting real-time data display, touch interaction, and industrial protocols (e.g., Modbus, CAN).
   • Advantages include rapid development, hardware acceleration (e.g., OpenGL), and modular design, making it ideal for industrial automation scenarios.

Application Features

1. Real-Time Monitoring and Control:
   • ARM-based Linux Computer offer high performance and low power consumption, ideal for real-time sensor data collection and control logic execution.
   • Qt is used to develop intuitive graphical interfaces to display device status, process flows, or alarm information, supporting user interaction via touchscreens or physical buttons.
   • Example: Production line equipment status monitoring, PLC control panels.
2. Human-Machine Interface (HMI):
   • Qt’s touchscreen support and rich UI components (e.g., buttons, charts, animations) enable a user-friendly interactive experience.
   • Supports dynamic data visualization, such as real-time curves or dashboards for temperature, pressure, speed, etc.
   • Example: Touchscreen control interfaces for factory equipment.
3. Multi-Device Integration:
   • ARM-based Linux Computer communicate with PLCs, sensors, or actuators via interfaces like serial ports (e.g., RS232/RS485), Ethernet, or CAN bus.
   • Qt provides network modules (e.g., TCP/IP, MQTT) to support interaction with host computers or cloud systems.
   • Example: Local control panels in distributed control systems.
4. Customization and Scalability:
   • Qt supports modular development, allowing customization of interfaces and functions for different automation scenarios.
   • ARM-based Linux Computer’ hardware expandability (e.g., GPIO, USB) supports connections to various peripherals.
   • Example: Control panels supporting different industrial protocols (e.g., Modbus, OPC UA).

Technical Implementation

1. Hardware Selection:
   • ARM Industrial Control Computer: Choose processors like NXP i.MX BL360 series, TI T507-H series BL340 series, or Rockchip RK3568 BL410 series, which offer sufficient computing power (Cortex-A series) and rich peripheral interfaces.
   • Display and Input: Pair with touchscreens (capacitive/resistive) or physical buttons, optimized for Qt’s touch capabilities.
   • Storage and Memory: Ensure adequate RAM (typically 1GB+) and Flash storage (8GB+) to run Qt applications and store data.
2. Qt Development:
   • Framework Choice: Use Qt Quick (based on QML) for lightweight, smooth interfaces suitable for embedded systems, or Qt Widgets for traditional desktop-style interfaces.
   • Functional Modules:
     • Data Visualization: Use Qt Charts or custom QML components to draw real-time curves, bar charts, or dashboards.
     • Communication Modules: Support serial communication via Qt’s SerialPort module or protocols like TCP/IP and MQTT via Qt Network.
     • Multilingual Support: Qt’s internationalization features enable multi-language switching to accommodate users in different regions.
   • Optimization: Use Qt’s embedded optimization tools (e.g., Boot to Qt) to reduce resource usage and improve startup speed.
3. System Environment:
   • Operating System: Run embedded Linux (e.g., Yocto, Buildroot) or RTOS (e.g., FreeRTOS) to support Qt’s cross-platform deployment.
   • Driver Support: Ensure the ARM-based Linux Computers touchscreen, GPU, and communication interfaces have suitable drivers to support Qt hardware acceleration.
4. Development Process:
   • Requirements Analysis: Define the control panel’s functions, such as data collection, control command issuance, and alarm handling.
   • Prototype Design: Use Qt Creator to design UI prototypes for rapid iteration.
   • Integration Testing: Deploy the Qt application to the ARM-based Linux Computer, testing interface responsiveness, communication stability, and real-time performance.
   • Optimization and Deployment: Streamline code, optimize resource usage, and adapt to target hardware.

Advantages

1. High Performance and Low Power Consumption:
   • ARM-based Linux Computer’ low power characteristics are suitable for long-term operation, while Qt’s hardware acceleration (e.g., OpenGL) ensures smooth graphical performance.
2. Rapid Development and Cross-Platform:
   • Qt supports fast UI development and cross-platform portability, reducing development costs and adapting to different ARM industrial control computer models.
3. Flexibility:
   • Supports multiple industrial protocols and hardware interfaces, accommodating various automation scenarios.
   • Qt’s modular design facilitates function expansion and maintenance.
4. User Experience:
   • Qt provides modern, responsive interfaces, enhancing operators’ user experience.
   • Supports touchscreens, multi-touch, and gesture operations.

Considerations

1. Resource Constraints:
   • ARM-based Linux Computer have limited memory and CPU resources, requiring optimized Qt applications to avoid performance bottlenecks from complex animations or high-resolution images.
   • Use Qt Quick Compiler or static compilation to reduce runtime overhead.
2. Real-Time Performance:
   • Automation control panels often require hard real-time responses, necessitating an operating system that supports real-time tasks (e.g., RTOS) or an optimized Linux kernel.
   • Ensure Qt’s event handling does not block critical control logic.
3. Reliability:
   • Industrial environments demand high reliability, requiring testing of Qt applications under conditions like high temperatures or vibrations.
   • Implement data backup and fault recovery mechanisms to prevent data loss from unexpected power outages.
4. Security:
   • Control panels may involve network communication, requiring Qt’s encryption modules (e.g., SSL/TLS) to secure data transmission.
   • Implement user authentication and permission management to prevent unauthorized operations.

Case Example

• Scenario: Control panel for an injection molding machine in a factory.
  • Hardware: ARM-based Linux Computer based on Rockchip RJ3568J BL410 series , equipped with a 7-inch capacitive touchscreen, running embedded Linux.
  • Functions:
    • Real-time display of temperature, pressure, and injection progress.
    • Support for manual/automatic mode switching to control the machine’s start/stop.
    • Communicate with PLC via Modbus RTU to collect sensor data.
    • Use Qt Charts to plot production data trends.
  • Implementation: Develop a touch-friendly interface using Qt Quick, integrate the Modbus library for communication, and optimize startup time to within 5 seconds.

Summary

The combination of ARM-based Linux Computer and Qt is an ideal choice for developing automation control panels, enabling high performance, reliability, and user-friendly interfaces. By selecting appropriate hardware, optimizing Qt applications, and adapting to industrial protocols, it can meet the needs of factory automation, equipment monitoring, and other scenarios.