There are organizations that are small enough to follow an informal or even undocumented process and still produce a product of sufficient quality to meet market needs. When these organizations attempt to develop a safety product, they inevitably fall short of meeting the requirements of IEC 61508. A formalized process that is reviewed and approved, along with project phase deliverables, are a major focus of the standard.
It can be hard to get buy-in from the development team…they just want to get something done. As a starting point, you have to put some infrastructure in place. ISO 9000 compliance is a good place to start, because a good quality management system (QMS) is a perfect foundation for a safety development process. This is a basic “say what you do and do what you say” system, and it provides formalized recording of your processes and a structured way to change and maintain them. Once your written processes are in place, you know what you have, and what you have not. But just as a house foundation does not provide shelter from the environment without walls and a roof, the QMS alone is not enough for a compliant IEC 61508 process.
In the overall development process, each phase is divided into elementary activities with the scope, inputs, and outputs specified for each phase. A V-Model approach considers these distinct phases:
- Architecture design
- Detailed design
- Unit test
- Integration test
- Validation test
In addition, there are three non-phase-specific processes that need to be considered:
- Documentation Management
- Configuration Management
- Functional Safety Management
These three areas provide support and structure across all of the development phases.