Systematic Failure

Definition:
Systematic Failures are failures related to design, implementation, or management errors rather than random hardware faults. This is often a software failure. This is tied with the concept of systematic compatibility and route “S”.

Key Points:

  • Must be addressed through processes like FSM and quality assurance.
  • Different from random failures that are statistically modeled.
  • Much of IEC 61508 is focused on removing these.
  • Can be eliminated after detection by changing design.
  • A proof test would not generally find these types of failures.

Example:
A software bug causing all sensors to report wrong values is a systematic failure.

See also: Systematic Capability, Random Failures

Cited Source:

  • IEC 61508-4:2010, Clause 3.6.9.

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