Simplifier Gateway

The Simplifier Gateway is an industrial functional-safety communication device developed as part of the Safety Simplifier ecosystem. It connects decentralized safety devices and safety I/O systems to higher-level industrial safety networks, enabling machine-safety data to be collected, processed, and forwarded to safety controllers. The device is certified up to SIL 3, making it suitable for demanding machine-safety applications that require a high level of diagnostic coverage, deterministic behavior, and compliance with functional safety standards such as IEC 61508.

The Gateway architecture contains two dedicated safety cores and one separate communication core. The safety cores are responsible for safety-related processing, diagnostics, monitoring, and validation of safety communication, while the communication core handles network-facing and non-safety communication tasks. This architectural separation supports clear responsibility boundaries between safety and communication functions. In addition to the existing PROFIsafe variant, an FSoE variant has also been developed and is currently submitted for SIL 3 certification.

My role in the project covered embedded firmware development, safety verification, automated testing, embedded DevOps, and certification evidence generation. I worked on bare-metal driver development, implementing low-level firmware components close to the hardware and ensuring that the software behavior met the deterministic and reliability requirements expected from a safety-certified embedded device.

A major part of my work was the development and maintenance of unit tests for the complete in-scope firmware of the safety cores. I achieved 100% statement and branch coverage for all in-scope safety firmware using a combination of HIL testing and fault insertion, excluding certified third-party components and toolchain libraries. To support this, I developed a custom unit testing framework tailored specifically to the Gateway's firmware architecture and safety-core constraints. This framework enabled systematic, repeatable, and traceable verification of safety firmware behavior and became an important part of the project's quality and certification workflow.

I was also involved in code reviews and architectural reviews, focusing on safety, maintainability, traceability, and compliance. I contributed to the project's software quality activities through MISRA analysis and enforcement, code complexity analysis, and the review of safety-relevant implementation decisions. These activities were not only internal quality measures, but also part of the formal evidence required for certification.

In addition, I created and maintained official documentation for the certification evidence package, including documents related to code reviews, unit testing, test coverage, MISRA compliance, MISRA deviations, and code quality analysis. These documents formed part of the official document release required by the certifying body when assessing the product for SIL 3 compliance.

I also solely developed and maintain the embedded DevOps infrastructure. This included building and maintaining CI pipelines for regular firmware builds, automatically executing unit tests and HIL tests on each build, and generating proof-of-review documentation from GitHub pull requests and review comments. This improved process traceability and helped ensure that review evidence could be collected and presented consistently during certification activities.

Beyond implementation and testing, I actively participated in functional safety and compliance meetings, helping to design, review, and verify the device architecture against IEC 61508 requirements. I also developed firmware upgrade utilities for field firmware updates over CAN bus, enabling controlled DFU procedures for deployed devices.

Overall, my work on the Simplifier Gateway combined low-level embedded development, safety-critical firmware verification, automated testing, compliance documentation, and certification support for a SIL 3 industrial safety device.