9.Developed firmware for industrial automation

Technologies:

C,C++, ARM Cortex-M4 microcontroller

Industry:

Industry Automation

Type:

Development, Support

Client Overview

The client is a midsized industrial automation firm specializing in designing and fabricating Programmable Logic Controllers (PLCs) and Human-Machine Interfaces (HMIs). Their products are extensively utilized in factory automation, process control, and IoT-enabled industrial ecosystems. With an elevated demand for intelligent, connected devices, the client sought to develop a next-generation PLC equipped with advanced real-time control, secure communications, and cloud integration functionalities. The project necessitated firmware development that was compliant with industrial standards (e.g., IEC 61131-3, IEC 62443) while functioning within the constraints of embedded hardware.

Objectives

Develop a real-time firmware solution for a new PLC architecture capable of managing multitasking, industrial communication protocols, and secure data exchange.
Ensure high reliability and low-latency performance critical to industrial applications.
Implement robust cybersecurity measures to safeguard against firmware tampering, unauthorized access, and data breaches.
Facilitate scalability and interoperability with existing systems, third-party devices, and cloud platforms.
Achieve compliance with industrial standards and certifications (e.g., ISO 27001, IEC 62443).

Requirements

Functional Requirements:

Real-time task scheduling with deterministic response times (<1 ms).
Support for multiple industrial communication protocols:
Modbus RTU/TCP for legacy integration.
Ethernet/IP for industrial Ethernet networks.
MQTT for IoT and cloud connectivity.
Establish secure firmware updates via Over-the-Air (OTA) mechanisms.
Implement remote diagnostics and monitoring through a cloud-based dashboard.
Ensure compatibility with existing HMI systems and third-party devices.

Non-Functional Requirements:

Reliability: Mean Time Between Failures (MTBF) exceeding 100,000 hours.
Performance: Real-time control with latency less than 1 ms.
Security: Secure boot, firmware integrity checks, and encrypted communication protocols (e.g., TLS 1.2/1.3).
Resource Efficiency: Optimized for a 32-bit ARM Cortex-M4 microcontroller with 512 KB flash and 128 KB RAM.
Power Efficiency: Low-power operation suitable for energy-sensitive applications.

Technical Constraints:

Limited hardware resources, including memory and processing power.
Requirement for backward compatibility with legacy systems.
Compliance with industrial safety and cybersecurity standards.

Approach

The firmware development process followed a V-Model methodology, integrating rigorous planning, iterative development, and extensive verification and validation. The methodology involved

Requirement Analysis: Engaged with stakeholders to define comprehensive and non-functional requirements.
System Architecture Design: Developed a modular, layered architecture for enhanced scalability and maintainability.
Prototyping: Created a proof-of-concept to validate key functionalities and performance criteria.
Implementation: Employed a phased strategy for implementation, prioritizing critical features.
Testing and Validation: Conducted unit testing, integration testing, and system-level validation to ensure thorough compliance with requirements.
Deployment and Support: Offered post-deployment assistance for firmware updates and remediation of any defects.

Development Process

Requirement Gathering and Analysis:

Conducted workshops with stakeholders to delineate use cases and technical constraints.
Documented requirements utilizing platforms such as Jira and Confluence.
Generated System Requirement Specifications (SRS) and Software Requirement Specifications (SRS).

System Architecture Design:

Formulated a layered architecture consisting of the following modules.
Hardware Abstraction Layer (HAL): Facilitating hardware-specific operations.
Real-Time Operating System (RTOS): Managing task scheduling and resource allocation.
Communication Stack: Supporting industrial protocols (Modbus, Ethernet/IP, MQTT).
Security Layer: Ensuring secure boot processes, firmware updates, and encrypted communications.
Application Layer: Providing user-defined logic and control algorithms.
Unified Modeling Language (UML) diagrams—including class and sequence diagrams—were used to model system behaviour and inter-module interactions.

Implementation:

Developed firmware using C/C++ to optimize performance and resource utilization.
Leveraged FreeRTOS for efficient real-time task scheduling and multitasking capabilities.
Integrated communication stacks:
Modbus: Implemented through open-source libraries (e.g., libmodbus).
Ethernet/IP: Developed a custom implementation for industrial Ethernet environments.
MQTT: Integrated Eclipse Paho for IoT communication.
Established secure boot and OTA firmware updates utilizing cryptographic frameworks (e.g., mbedTLS).
Optimized memory consumption through dynamic memory allocation and memory pooling techniques.

Testing and Validation:

Unit Testing: Employed Ceedling and Unity frameworks for automated unit testing.
Integration Testing: Verified inter-module interactions through hardware-in-the-loop (HIL) testing.
System Testing: Validated real-time performance and latency using oscilloscopes and logic analyzers.
Security Testing: Conducted penetration and fuzz testing to identify and mitigate vulnerabilities.
Compliance Testing: Ensured adherence to IEC 61131-3 and IEC 62443 industrial standards.

Deployment:

Delivered comprehensive documentation encompassing user manuals, API specifications, and troubleshooting guides.
Conducted training sessions for the client’s engineering team on firmware maintenance and update protocols.
Implemented a Continuous Integration/Continuous Deployment (CI/CD) pipeline to facilitate ongoing firmware updates.

Strategies Employed to Achieve the Solution

Modular Design: Employed a modular architecture to enhance code reusability and simplify maintenance processes.
Agile Development: Utilized Agile methodologies to provide incremental firmware updates, allowing for iterative client feedback and validation.
Risk Management: Proactively identified potential risks (e.g., resource constraints, security vulnerabilities) and executed mitigation strategies early in the project lifecycle.
Compliance Focus: Ensured strict adherence to industry standards through comprehensive testing and meticulous documentation practices.
Resource Optimization: Leveraged static code analysis tools (e.g., PC-Lint) and profiling tools (e.g., Percepio Tracealyzer) to optimize system performance and memory utilization.

Business Outcomes

Product Launch: The new PLC was successfully launched within the predefined timeline, garnering favourable market reception.
Increased Market Share: The firmware’s advanced functionality and reliability enabled the client to secure new contracts and broaden its customer base.
Operational Efficiency: The modular design approach resulted in a 30% reduction in development time for subsequent firmware iterations.
Enhanced Security: Deployment of secure boot mechanisms and over-the-air (OTA) update capabilities significantly mitigated cybersecurity risks, bolstering customer trust.
Compliance: Attained certifications for IEC 61131-3 and IEC 62443, elevating the product’s market viability.

Technologies and Tools Used

Programming Languages: C, C++
Real-Time Operating System (RTOS): FreeRTOS
Communication Protocols:
Modbus (libmodbus)
Ethernet/IP (custom implementation)
MQTT (Eclipse Paho)
Security Libraries:
mbedTLS for cryptographic functions and secure boot
Secure Hash Algorithms (SHA-256) for firmware integrity verification
Development Tools:
Integrated Development Environments (IDEs): Eclipse, VS Code
Version Control Systems: Git/GitLab
Testing Frameworks: Ceedling, Unity
Static Code Analysis: PC-Lint
Profiling Tools: Percepio Tracealyzer
Hardware Platform: 32-bit ARM Cortex-M4 microcontroller
Documentation Tools: Doxygen, Confluence

Conclusion

The firmware development initiative yielded a robust, scalable, and secure solution for the client’s next-generation PLC. The project fulfilled its objectives and delivered substantial business value by employing a methodical development process, leveraging cutting-edge technologies, and maintaining a rigorous compliance focus. The client is now strategically positioned to compete in the dynamic industrial automation sector with a product that adheres to the highest performance, reliability, and security standards.