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Safety & Constraints Fundamentals

Safety & Constraints Fundamentals

Use this page to revise how safety and physical constraints show up in embedded work — vocabulary, not a certification course.

Hazard vs. risk

A hazard is a potential source of harm (moving arm, hot driver, stored energy). Risk combines severity and likelihood. A mitigation reduces risk (guard, current limit, watchdog, e-stop) but rarely to zero; residual risk must be stated.

Electrical and mechanical basics

  • Stay inside absolute maximum ratings and prefer recommended operating conditions.
  • Isolation, fusing, and not probing mains are lab rules, not optional style.
  • Actuators need a defined safe state when firmware dies or comms drop.

Standards awareness

Names you should recognise: IEC 61508 (functional safety), machinery / CE for products in the EU, radio/EMC if you transmit, GDPR if you process personal sensor data. Student prototypes are not certified products; claiming they are is incorrect.

Starting Points

Key Points

  • You can distinguish hazard, risk, mitigation, and residual risk.
  • You can explain absolute maximum ratings vs. recommended operating conditions.
  • You can name a safe state for a typical actuator when control is lost.
  • You can name at least one relevant legal or standards frame and say what it is for, without claiming certification.