IEC 61784-3-8:2021

Overview

IEC 61784-3-8:2021 is an international standard published by the International Electrotechnical Commission (IEC) that defines functional safety communication profiles for industrial communication networks. Specifically, it focuses on Functional Safety Fieldbuses and provides additional specifications for Communication Profile Family 8 (CPF 8). This standard establishes a safety communication layer, including services, protocols, and management mechanisms, based on CPF 8 defined in IEC 61784-1, IEC 61784-2, and IEC 61158 Type 18 and Type 23.

The purpose of IEC 61784-3-8:2021 is to ensure robust and reliable transmission of safety-related messages within distributed fieldbus networks, supporting compliance with the stringent requirements of IEC 61508 for functional safety. It targets implementation in safety devices only, and explicitly excludes coverage of electrical safety and intrinsic safety, which relate to hazards such as electrical shock or explosive atmospheres.

Key Topics

• Safety Communication Layer
  This layer defines essential services and protocols for safe message transmission, error detection, and fault tolerance to guarantee the integrity and confidentiality of safety data within industrial networks.

• CPF 8 Profiles
  The document specifies two key profiles within CPF 8:

  • FSCP 8/1 (e.g., CC-Link Safety™)
  • FSCP 8/2 (e.g., CC-Link IE™ Safety communication function)
    Both profiles include detailed normative references, definitions, communication protocols, system requirements, and safety function response time guidelines.

• Safety Measures
  IEC 61784-3-8 defines multiple safety measures such as redundancy, cyclic data monitoring, message authentication, and timing requirements crafted to meet functional safety standards for industrial automation.

• System Requirements and Assessment
  The standard emphasizes the importance of installation guidelines, maintenance procedures, safety manuals, and rigorous assessment processes to validate that devices comply with functional safety criteria.

• Management Services and Protocol State Machines
  Managing connection establishment, termination, and error handling using defined state machines ensures reliable network operation compatible with safety requirements.

Applications

IEC 61784-3-8:2021 is essential for industries relying on process control, manufacturing automation, and machinery safety where functional safety communication is critical. Its applications include:

• Automation Safety Networks
  Facilitating safe communications between controllers, sensors, actuators, and safety devices in factory automation systems.

• Process Industries
  Providing safety communication protocols for hazardous or complex processes where safety integrity is mandatory.

• Machinery Safety Systems
  Enabling reliable safety message exchange in machine control networks to protect personnel and equipment from risks.

This standard helps developers design safety-compliant products and assists assessors in ensuring systems meet stringent compliance for functional safety.

Related Standards

IEC 61784-3-8:2021 references and complements several other key international standards to support functional safety communication in industrial networks:

• IEC 61508 – Functional safety of electrical/electronic/programmable electronic safety-related systems
• IEC 61784-1 and IEC 61784-2 – Communication profile families and wiring/data link layer aspects
• IEC 61158 (Type 18 and Type 23) – Fieldbus specifications including data link and physical layer details
• IEC 61784-3 – General requirements for functional safety communication profiles

These connected standards provide comprehensive frameworks for ensuring end-to-end safety and interoperability in industrial communication systems.

Keywords: IEC 61784-3-8, CPF 8, functional safety fieldbuses, safety communication layer, industrial communication networks, CC-Link Safety, IEC 61508 compliance, functional safety protocol, distributed network safety, manufacturing automation safety, process control safety communication.