IEC 61784-3-3:2021

IEC 61784-3-3:2021 Overview

IEC 61784-3-3:2021 is an international standard issued by the International Electrotechnical Commission (IEC) that specifies the functional safety communication layer for industrial networks based on CPF 3 profiles. This standard defines safety communication services and protocols grounded in CPF 3 of IEC 61784-1 and IEC 61784-2, along with IEC 61158 Types 3 and 10. Its primary focus is on enabling reliable and secure transmission of safety-relevant messages within distributed fieldbus networks, specifically designed for implementation in safety devices only.

Notably, IEC 61784-3-3:2021 does not address electrical safety or intrinsic safety; rather, it focuses solely on functional safety related to communication protocols. The standard aligns with IEC 61508 requirements for functional safety across various industrial applications like process control, manufacturing automation, and machinery.

This document serves as a crucial guideline for developers and assessors of safety-compliant devices and systems, emphasizing the necessary communication profiles to achieve high integrity and reliable safety performance in industrial environments.

Key Topics of IEC 61784-3-3:2021

• Functional Safety Communication Layer: Defines protocols and services to ensure safe communication across CPF 3-based fieldbuses.
• Safety Protocol Specifications: Covers the detailed structure of Safety PDUs, monitoring mechanisms (e.g., MonitoringNumber), CRC signatures, and error detection/reaction strategies.
• Safety Measures and Requirements: Outlines safety functions including watchdog timers, safety alarms, and diagnosis for communication integrity.
• Communication Model: Describes device models and communication relationships, covering F-Host and F-Device driver implementations.
• Safety Parameterization: Provides mechanisms for safety parameter assignment, data security, and configuration management to maintain system integrity.
• System Requirements: Addresses installation guidelines, safety response times, maintenance procedures, and considerations for wireless transmission channels.
• Safety and Security Interrelation: Explores the balance and interaction between functional safety and cybersecurity in communication protocols.
• Compliance Guidelines: Assists device developers and safety assessors in implementing and validating CPF 3 safety communication profiles.
• Safety Communication Profile FSCP 3/1 (PROFIsafe™): Includes additional specifications detailing PROFIsafe operation within CPF 3 networks.

Practical Applications

IEC 61784-3-3:2021 is essential for industrial sectors requiring rigorous safety communication protocols:

• Process Control Systems: Ensures safe data exchange in chemical plants, oil and gas installations, and refineries, where safety communication plays a critical role.
• Manufacturing Automation: Supports safety communication for automated machinery and robotics, preventing hazards due to communication faults.
• Machinery Safety: Provides safe networking solutions for machinery controls where functional safety is mandated by regulatory standards.
• Distributed Safety Devices: Enables safety-relevant communication between distributed safety devices, such as emergency stops, sensors, and safety controllers.
• Safety-Critical Network Design: Helps network architects design systems that meet SIL (Safety Integrity Level) requirements based on functional safety communication profiles.
• Safety Device Development: Provides manufacturers with the necessary communication standards to develop safety-compliant devices.
• Safety Assessment and Certification: Serves as a reference for safety assessors and certification bodies to evaluate compliance with functional safety communication requirements.

Related Standards

• IEC 61784-1: Profiles for industrial communication networks – provides the foundational CPF profiles referenced by IEC 61784-3-3.
• IEC 61784-2: Defines specific communication protocol profiles including CP 3/1 to CP 3/6, which underpin CPF 3 safety communications.
• IEC 61158: Standardizes industrial communication networking protocols, including Types 3 and 10 used in this safety communication layer.
• IEC 61508: The overarching standard for functional safety of electrical/electronic systems, establishing principles that guide IEC 61784-3-3.
• IEC 61784-3: Addresses functional safety communication principles that apply across various safety communication layers and protocols.
• ISO 13849-1: Related for machinery safety and safety-related control systems, complementing communication safety standards.

By implementing IEC 61784-3-3:2021, industries ensure robust and dependable functional safety communication over fieldbus networks, facilitating compliance with international safety regulations and enhancing overall system reliability in critical applications.

Keywords: IEC 61784-3-3, functional safety fieldbuses, CPF 3, safety communication layer, industrial communication networks, PROFIsafe, IEC 61508, safety protocols, safety device standards, industrial automation safety, safety network communication, functional safety standards.