IEC 61784-3-13:2016

Overview

IEC 61784-3-13:2016 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies a safety communication layer for industrial communication networks, focusing on functional safety fieldbuses. This particular part, titled Functional Safety Fieldbuses – Additional Specifications for CPF 13, defines protocols and services based on the CPF 13 profile from IEC 61784-2 and IEC 61158 Type 13. The safety communication layer is specifically designed for implementation in safety devices within industrial automation systems.

This second edition represents a comprehensive technical revision of the 2010 release, introducing key updates such as the adoption of openSAFETY trade name, new Slim Safety Protocol Data Unit (PDU), enhanced Safety Object Dictionary (SOD) with CRC, additional block transfer services, and improved connection protocols. The standard serves as a critical foundation for secure and reliable data exchange in safety-relevant industrial networks, ensuring compliance with stringent functional safety requirements.

Key Topics

• Safety Communication Layer Architecture
  IEC 61784-3-13 outlines a structured safety communication layer that integrates with Fieldbus Access Layer (FAL), Data Link Layer (DLL), and Physical Layer (PhL), providing a robust framework for safety data transmission.

• Safety Protocol Data Units (PDUs)
  The standard specifies formats and fields of Safety PDUs, including address fields, identifiers, cyclic redundancy checks (CRC-8/CRC-16), time request and response mechanisms, ensuring data integrity and timely delivery.

• Safety Process Data Objects (SPDO)
  Defines the data types, transmission modes, and error handling processes for SPDOs, which form the core of real-time safety data exchange between devices.

• Safety Service Data Objects (SSDO)
  Introduces services for safe configuration and diagnostics, including segmented and block transfers necessary for efficient device commissioning and maintenance.

• Safety Network Management (SNMT)
  Provides protocols for network management, startup sequences, power-up/down operations, address verification, commissioning mode, and recovery from errors or restarts, ensuring continuous safety during network lifecycle stages.

• Safety Object Dictionary (SOD)
  Details the structure and data types of the SOD, enabling standardized representation of safety-related objects, facilitating consistent device interoperability.

• Technical Enhancements
  Latest edition features additions such as the Slim Safety PDU, connection valid bit for SPDOs, user-defined parameters writable during operation, and retries management to enhance fault tolerance and system robustness.

Applications

IEC 61784-3-13:2016 is pivotal in industrial automation and control systems requiring certified functional safety communication. Typical applications include:

• Safety Instrumented Systems (SIS) in process industries, ensuring safe shutdown or emergency actions.
• Factory automation where safety devices such as emergency stops, light curtains, and safety PLCs communicate critical safety data.
• Robotics and machinery control requiring real-time, fail-safe data exchange to minimize risks to operators and equipment.
• Automotive manufacturing lines that rely on reliable safety fieldbus communication for collision avoidance and system monitoring.
• Oil & Gas, Chemical, and Power Generation sectors, where strict functional safety standards are mandatory to avoid catastrophic failures.

The standard supports implementation of safety devices that comply with international safety certifications by providing a clear, interoperable communication profile tailored to functional safety requirements.

Related Standards

• IEC 61784-2: Profiles for Industrial Communication Networks – Part 2, providing detailed definitions of Communication Profiles including CPF 13, on which IEC 61784-3-13 builds.
• IEC 61158: Fieldbus Standards addressing communication protocols and physical layers operating in industrial networks.
• IEC 61784-3: Functional Safety Communication Profiles that presents common rules and principles essential for safety communication layers.
• IEC 61508: Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems, overarching standard for safety lifecycle and validation.
• IEC 61850: Communication networks and systems in substations, for related safety communications in power automation.

By aligning with these standards, IEC 61784-3-13 ensures comprehensive safety communication compliance, interoperability across devices and vendors, and supports the growing demands of Industry 4.0 and smart factory implementations.

Keywords: IEC 61784-3-13, functional safety fieldbus, CPF 13, openSAFETY, safety communication layer, safety protocols, industrial automation safety, safety process data object, safety service data object, safety network management, industrial communication networks, IEC standards, functional safety communication.