IEC 61784-3-2-2021 PDF

Full title and description

Industrial communication networks - Profiles - Part 3-2: Functional safety fieldbuses - Additional specifications for CPF 2. This document specifies a safety communication layer (services and protocol) based on CPF 2 of IEC 61784-1, IEC 61784-2 and IEC 61158 Type 2, intended for implementation in safety devices and providing mechanisms for transmission of safety‑relevant messages in distributed fieldbus networks in accordance with IEC 61508 requirements.

Abstract

IEC 61784-3-2:2021 defines a safety communication layer (services and protocol) built on CPF 2 and related IEC profile/protocol layers. It identifies functional safety communication principles relevant to this layer, describes mechanisms for safe transmission of safety‑relevant messages over fieldbus technology, and provides guidance for developers and assessors of compliant devices and systems. It does not cover electrical safety, intrinsic safety or security requirements.

General information

• Status: Current international standard (active; stability date indicated to 2026).
• Publication date: 19 May 2021.
• Publisher: International Electrotechnical Commission (IEC).
• ICS / categories: 25.040.40; 35.100.05.
• Edition / version: Edition 4.0 (IEC 61784-3-2:2021).
• Number of pages: 579 pages.

(Product details such as publication date, edition and page count are taken from the IEC product listing for IEC 61784-3-2:2021.)

Scope

Specifies additional requirements and a safety communication layer for CPF 2 that enable safe exchange of safety‑related messages between participants in a distributed fieldbus network. The standard aligns these mechanisms with the requirements in IEC 61508 for functional safety and is intended for implementation in safety devices; it explicitly excludes electrical safety, intrinsic safety and dedicated security requirements.

Key topics and requirements

• Definition of a safety communication layer (services and protocol) based on CPF 2 and IEC 61158 Type 2.
• Principles and mechanisms for transmission of safety‑relevant messages over fieldbus networks.
• Mapping and conformance requirements to ensure compatibility with IEC 61784-1 / IEC 61784-2 profile layers.
• Conformance guidance for device developers and assessors to meet IEC 61508 functional safety expectations.
• Explicit statements on exclusions: electrical safety, intrinsic safety and security requirements are not covered.

These topics and requirements are summarized from the standard’s scope and product description.

Typical use and users

Used by safety device implementers, fieldbus protocol and device vendors, control‑system suppliers, system integrators, safety assessors and certification bodies. Typical applications include process control, manufacturing automation and machinery where functional safety communications over fieldbus are required.

Related standards

IEC 61784 series (especially IEC 61784-1 and IEC 61784-2), IEC 61158 (fieldbus types and protocol details), IEC 61784-3 (other parts addressing functional safety communications), and IEC 61508 (functional safety framework and requirements). National/adopted versions (EN/UNE/ČSN/etc.) exist for regional application.

Keywords

functional safety, safety communication layer, CPF 2, fieldbus, IEC 61784-3-2, IEC 61158, IEC 61508, distributed control, safety devices, industrial communication networks.

FAQ

Q: What is this standard?

A: IEC 61784-3-2:2021 is an international standard that defines a safety communication layer and additional specifications for CPF 2 to support transmission of safety‑relevant messages over fieldbus networks in accordance with functional safety requirements.

Q: What does it cover?

A: It covers services, protocol details and rules for a CPF 2-based safety communication layer, principles relevant to functional safety communications, and guidance for developers and assessors; it does not cover electrical safety, intrinsic safety or security requirements.

Q: Who typically uses it?

A: Device manufacturers, protocol implementers, system integrators, safety engineers, assessors and certification bodies working on safety devices and safety-related fieldbus communications in industrial automation.

Q: Is it current or superseded?

A: IEC 61784-3-2:2021 is the current edition published 19 May 2021 (Edition 4.0) with stability information listed through 2026; it supersedes earlier editions such as the 2010 edition.

Q: Is it part of a series?

A: Yes — it is part of the IEC 61784 series (Profiles), specifically part 3 (functional safety fieldbuses). It references and depends on other parts of IEC 61784, IEC 61158 and the IEC 61508 functional safety framework.

Q: What are the key keywords?

A: Functional safety, safety communication layer, CPF 2, fieldbus, IEC 61784, IEC 61158, IEC 61508, safety devices, distributed network.