SIST EN 62061:2021/kprA2:2025
(Amendment)Amendment 2 - Safety of machinery - Functional safety of safety-related control systems
Amendment 2 - Safety of machinery - Functional safety of safety-related control systems
Sicherheit von Maschinen - Funktionale Sicherheit sicherheitsbezogener Steuerungssysteme
Amendement 2 - Sécurité des machines - Sécurité fonctionnelle des systèmes de commande relatifs à la sécurité
Varnost strojev - Funkcijska varnost nadzornih sistemov, povezanih z varnostjo
General Information
Relations
Overview
EN IEC 62061:2021/FprA2:2025 - Amendment 2 updates the functional safety requirements for safety-related control systems (SCS) of machinery. Published as a committee draft for vote (CDV) in 2025 with a proposed stability date of 2027, this amendment refines diagnostic, fault‑reaction and subsystem classification rules used to achieve required Safety Integrity Levels (SILs). Note: the document in the extract is a draft under parallel IEC/CENELEC voting and remains subject to change.
Key topics and requirements
- Diagnostic functions and systematic integrity: Diagnostic functions must meet systematic safety integrity requirements (see clause 7.3.2). Diagnostics are required to detect dangerous failures and trigger specified fault‑reaction functions to reach or maintain a safe state.
- Detection timing and testing: For subsystems with zero hardware fault tolerance (HFT = 0) that rely on diagnostics, either the diagnostic test rate to demand rate shall be ≥ 100 or testing must occur immediately on demand; detection plus fault reaction must prevent a dangerous situation.
- Hardware Fault Tolerance (HFT) and isolation: Amendment 2 clarifies that for certain machines a faulty channel of a subsystem with HFT ≥ 1 may be isolated while the machine continues operating for up to an estimated maximum isolation time. If not repaired within that interval, an immediate fault reaction to a safe state is required.
- Safe Failure Fraction (SFF) and SIL attainment: The text updates notes on SFF thresholds and conditions where subsystems with SFF < 60% and HFT = 0 using well‑tried components or when faults are excluded may still be considered to achieve SIL 1 (see 7.5.3).
- Probability of dangerous failure per hour (PFH) guidance: The amendment provides a simplified approach to estimate PFH of diagnostic functions. If PFH is within one order of magnitude greater than the allowed PFH, additional periodic testing (minimum 10 equal-interval checks during proof-test interval) is recommended.
- Component classification: Emergency stop devices and enabling switches are explicitly addressed - they can be treated as HFT = 0 or HFT = 1 subsystems depending on the number of electrical output contacts (references: IEC 60947‑5‑5, ISO 13850, IEC 60947‑5‑8).
Applications and users
- Machine builders and OEMs designing safety-related control systems
- Functional safety engineers assigning SILs, SFF, HFT and PFH values
- Control-system integrators and safety assessors preparing validation and proof-test strategies
- Certification bodies and notified bodies evaluating machine safety compliance
- Safety managers implementing diagnostic and fault‑reaction policies on production equipment
Related standards
- IEC 62061 (main standard)
- IEC 61508 (functional safety of electrical/electronic/programmable systems) - referenced for additional guidance
- IEC 60947‑5‑5, IEC 60947‑5‑8, ISO 13850 (emergency stop and enabling device specifications)
Keywords: EN IEC 62061 amendment 2, functional safety, safety-related control systems, SIL, HFT, SFF, PFH, machine safety, diagnostic functions.
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 62061:2021/oprA2:2025
01-maj-2025
Varnost strojev - Funkcijska varnost nadzornih sistemov, povezanih z varnostjo
Amendment 2 - Safety of machinery - Functional safety of safety-related control systems
Sicherheit von Maschinen - Funktionale Sicherheit sicherheitsbezogener
Steuerungssysteme
Amendement 2 - Sécurité des machines - Sécurité fonctionnelle des systèmes de
commande relatifs à la sécurité
Ta slovenski standard je istoveten z: EN 62061:2021/prA2:2025
ICS:
13.110 Varnost strojev Safety of machinery
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
SIST EN 62061:2021/oprA2:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
SIST EN 62061:2021/oprA2:2025
SIST EN 62061:2021/oprA2:2025
44/1058/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 62061/AMD2 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2025-03-28 2025-06-20
SUPERSEDES DOCUMENTS:
44/1027/CD, 44/1043A/CC
IEC TC 44 : SAFETY OF MACHINERY - ELECTROTECHNICAL ASPECTS
SECRETARIAT: SECRETARY:
United Kingdom Mrs Nyomee Hla-Shwe Tun
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
SC 65A
ASPECTS CONCERNED:
Safety
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some
Countries” clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is
the final stage for submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).
TITLE:
Amendment 2 - Safety of machinery - Functional safety of safety-related control systems
PROPOSED STABILITY DATE: 2027
NOTE FROM TC/SC OFFICERS:
download this electronic file, to make a copy and to print out the content for the sole purpose of preparing National
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SIST EN 62061:2021/oprA2:2025
IEC CDV 62061/AMD2 ED2 © IEC 2025 2 44/1058/CDV
1 INTERNATIONAL ELECTROTECHNICAL COMMISSION
2 ____________
4 SAFETY OF MACHINERY –
5 FUNCTIONAL SAFETY OF SAFETY-RELATED CONTROL SYSTEMS
7 AMENDMENT 2
9 FOREWORD
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Frequently Asked Questions
SIST EN 62061:2021/kprA2:2025 is a draft published by the Slovenian Institute for Standardization (SIST). Its full title is "Amendment 2 - Safety of machinery - Functional safety of safety-related control systems". This standard covers: Amendment 2 - Safety of machinery - Functional safety of safety-related control systems
Amendment 2 - Safety of machinery - Functional safety of safety-related control systems
SIST EN 62061:2021/kprA2:2025 is classified under the following ICS (International Classification for Standards) categories: 13.110 - Safety of machinery; 25.040.40 - Industrial process measurement and control; 25.040.99 - Other industrial automation systems; 29.020 - Electrical engineering in general. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN 62061:2021/kprA2:2025 has the following relationships with other standards: It is inter standard links to SIST EN IEC 62061:2021. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
SIST EN 62061:2021/kprA2:2025 is associated with the following European legislation: EU Directives/Regulations: 2006/42/EC; Standardization Mandates: M/396. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
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