Functional Safety Certification for Welding Robots: IEC 61800-5-2 Explained

Date
2026-10-29
Location
Online
Host
Zach L

About this event

A Lunch-and-Learn for Electrical Engineers pursuing functional safety certification. A live 30-minute lunch-and-learn on IEC 61800-5-2 (Adjustable Speed Drives - Safety Functions) for welding robots, built for electrical engineers pursuing functional safety certification. What We'll Cover: What IEC 61800-5-2 (Adjustable Speed Drives - Safety Functions) requires and how its scope applies to welding robots Mapping IEC 61800-5-2 clauses to the certification evidence assessors expect System-specific hazards and safety functions typical of welding robots Common findings that delay certification, and how to avoid them A practical readiness roadmap for electrical engineers preparing for assessment Related topics: IEC 61800-5-2 · Welding Robots · functional safety certification · functional safety

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About IEC 61800-5-2 (Adjustable Speed Drives - Safety Functions)

This event covers the compliance, engineering, and verification requirements defined by IEC 61800-5-2.

IEC 61800-5-2 specifies safety requirements for adjustable speed power drive systems providing integrated safety functions — STO, SS1, SS2, SOS, SLS, SDI, SBC and others — enabling drive-based safeguarding without external contactors.

What it regulates

Definition and behavior of drive safety functions, their SIL capability claims, integration requirements, and the information the drive manufacturer must provide for machine-level PL/SIL verification.

Who must comply

Drive manufacturers claiming integrated safety, and machine builders using drive functions as subsystems in ISO 13849/IEC 62061 safety functions.

Key requirements of IEC 61800-5-2

  • Function definitions: Safe Torque Off, Safe Stop 1/2, Safe Operating Stop, Safely-Limited Speed, Safe Direction, Safe Brake Control, and more
  • Design per IEC 61508 with machinery-context clarifications
  • Required safety manual content: PFH, SIL CL, reaction times, constraints
  • Verification and validation of the integrated functions

Key concepts: IEC 61800-5-2

Reaction time
The drive's guaranteed time from demand to safe condition, entering the machine's safety-distance calculations.
STO (Safe Torque Off)
Removal of torque-producing energy to the motor without switching the supply — the foundational drive safety function, typically the final element of e-stop circuits.
SLS
Safely-Limited Speed — monitored speed ceiling enabling safe process observation or collaborative operation.
SS1 vs SS2
Controlled deceleration then STO (SS1) versus controlled stop with position held under monitoring (SS2/SOS).

Frequently asked questions: IEC 61800-5-2

Can drive-integrated functions replace contactors?

Yes — with a drive claiming suitable SIL CL/PL and applied per its safety manual, hardwired contactor pairs are commonly eliminated, simplifying panels while maintaining the required integrity.

Does STO stop the motor immediately?

STO removes torque; the motor coasts unless mechanics or a brake stop it. Where coasting is hazardous, SS1 (controlled deceleration then STO) or a safe brake function is selected instead.

Standard information based on the published text of IEC 61800-5-2 (Adjustable Speed Drives - Safety Functions). Event content is provided by the host. For authoritative guidance, consult the official standard body.