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Glossary · Safety standards

IEC 61800-5-2

German: IEC 61800-5-2

IEC 61800-5-2 is the international standard that specifies functional safety requirements for adjustable speed electrical power drive systems suitable for safety-related applications (PDS(SR)), including definitions of drive safety functions such as Safe Torque Off, Safe Stop 1 and Safely-Limited Speed.

  • Standards

In one sentence

IEC 61800-5-2 specifies functional safety requirements for drive systems and defines drive safety functions such as STO, SS1 and SLS.

Example

A servo drive datasheet states that its STO function meets SIL 3 according to IEC 61800-5-2 and PL e according to ISO 13849-1.

How it applies

  • Engineering: The standard defines the names and behavior of drive safety functions (Safe Torque Off (STO), Safe Stop 1 (SS1), Safe Operating Stop (SOS), Safely-Limited Speed (SLS) and others) and how their safety integrity is specified, based on IEC 61508.
  • Integration: A drive's rated safety function is one subsystem; the machine builder still has to design, verify and validate the complete safety function.
  • Documentation: The drive's safety manual must describe the conditions under which the stated safety values apply; machine documentation should reference those conditions rather than just the SIL or PL figure.
  • Selection: Compare the safety functions a drive offers, their ratings and required external components before choosing a drive for a safety concept.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: IEC 61800-5-2, Adjustable speed electrical power drive systems — Part 5-2: Safety requirements — Functional

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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