ISO 13849 Performance Level (PL a–e, Category B–4) / Safety Integrity Level (SIL, IEC 62061/61508)

ISO 13849 性能等级 PL（安全完整性等级 SIL）PL / SILAdvanced

Rating scales for how reliably a machine's safety functions work: ISO 13849's PL a–e, and the IEC family's SIL.

Functional safety asks whether safety functions such as emergency stop, protective stop, and speed limiting can be relied on to actually trigger when needed. ISO 13849-1 (current 2023 edition) measures this with a Performance Level, rising from a to e, corresponding to a per-hour probability of dangerous failure PFHd — PL d, for example, is 10⁻⁷ to 10⁻⁶. A required level PLr is first set from injury severity, exposure frequency, and whether the hazard is avoidable; the achieved PL is then computed from the architecture Category (B, 1, 2, 3, 4 — Categories 3 and 4 require that a single fault not lose the safety function), the mean time to dangerous failure (MTTFd) of components, and diagnostic coverage (DC), and must be no lower than PLr. The other major scale is IEC 61508's SIL 1–4, whose machinery-specific version IEC 62061 uses SIL 1–3; the two roughly correspond by PFHd: PL b/c ≈ SIL 1, PL d ≈ SIL 2, PL e ≈ SIL 3.

ExampleThe 2011 edition of ISO 10218-1 required all safety-related control functions on industrial robots to uniformly reach PL d, Category 3; the 2025 edition instead assigns a default level per function — a protective stop, for example, defaults to PL d or SIL 2, adjustable if the risk assessment allows.

Also called: PL, SIL, Performance Level, Safety Integrity Level, ISO 13849-1:2023, IEC 62061, IEC 61508, PL d, SIL 2
Related: Functional Safety · Safe Torque Off (STO) · Emergency Stop · Protective Stop · ISO 10218-1/-2:2025 Robotics — Safety Requirements · ISO 25785-1 (Safety Requirements for Industrial Mobile Robots with Actively Controlled Stability — Part 1: Robots)
Sources: ISO 13849-1:2023 Safety of machinery — Safety-related parts of control systems — Part 1
Spilma: ISO 13849 and IEC 62061: machinery functional safety
IBF Solutions: New standards for industrial robots EN ISO 10218-1 and -2
As of: 2025-02