Common Cause Failure
Single fault affecting multiple redundant safety channels simultaneously.
Key Takeaways
- Single fault affecting multiple redundant safety channels simultaneously.
- Advanced-level topic in Safety Systems
Detailed Definition
Single fault affecting multiple redundant safety channels simultaneously. This term is essential for understanding safety systems in industrial automation and PLC programming. It represents a key concept that professionals encounter regularly in their work with control systems and automation projects.
Common Cause Failure is a concept that appears in the design and review of safety-rated control systems — the equipment and procedures that keep machinery from injuring people when something goes wrong. Single fault affecting multiple redundant safety channels simultaneously.
Safety design separates the function from the standard control logic. Common Cause Failure is implemented or evaluated against ISO 13849-1 performance levels (PL a–PL e) or IEC 61508 / IEC 61511 SIL ratings, with redundancy, diagnostic coverage, and proof-test intervals all factored into the calculation.
In a real plant, Common Cause Failure is verified during commissioning by physically testing the safety function from every operator location, and the test result is logged. Without that signed test record, the safety case is incomplete regardless of how good the wiring is.
Common Questions
What is Common Cause Failure?
Single fault affecting multiple redundant safety channels simultaneously.
What prerequisites are needed to understand Common Cause Failure?
As an advanced-level concept, Common Cause Failure requires a solid foundation in PLC fundamentals and intermediate programming concepts. It's recommended to have hands-on experience with Safety Systems before diving deep into this topic.
What are related concepts I should learn?
To fully understand Common Cause Failure, you should also familiarize yourself with Emergency Stop, Safety PLC, and GuardLogix. These concepts work together in industrial automation systems.
Continue Learning
Ready to deepen your understanding of Common Cause Failure? Here are some recommended resources:
Was this helpful?
Let us know if this glossary term helped you understand Common Cause Failure better.
Your feedback helps us improve our glossary and create better content for the PLC programming community.
About Safety Systems
Safety PLCs, interlocks, and protective devices