IEC 61784-2-20:2023

Overview

IEC 61784-2-20:2023 is an international standard published by the International Electrotechnical Commission (IEC), focused on defining industrial network communication profiles. This particular document specifies Communication Profile Family 20 (CPF 20), which addresses additional real-time fieldbus profiles based on ISO/IEC/IEEE 8802-3, the standard commonly known as Ethernet. CPF 20 facilitates the integration of Real-Time Ethernet (RTE) technologies in industrial environments, ensuring predictable and reliable real-time data transfer and efficient synchronization between automation equipment.

Both implementers and end users of industrial automation and process control systems benefit from well-defined RTE network profiles, which promote interoperability, performance transparency, and easier integration of different vendors' solutions.

Key Topics

• Communication Profile Family (CPF) 20: Focuses on RTE communication profiles using standard Ethernet as a base, with additional capabilities for industrial requirements.
• Profiles Covered:
  • CP 20/1: ADS-net technology utilizing ring topology, suitable for reliable and redundant communication paths.
  • CP 20/2: ADS-net technology using star or linear topology, supporting flexible and scalable network layouts.
• Layered Approach: CPF 20 specifies usage of standardized Data Link Layer and Application Layer protocols, ensuring alignment with IEC 61158 and ISO/IEC/IEEE 8802-3.
• Performance Indicators: The standard defines and details critical real-time communication performance indicators, such as:
  • Delivery time
  • Number of end-stations
  • Network topology
  • Throughput (RTE)
  • Non-RTE bandwidth
  • Redundancy recovery time
• Dependency Tracking: Relationships and dependencies between performance indicators are specified, providing clarity when evaluating or designing network architectures.

Applications

IEC 61784-2-20:2023 is highly relevant in industrial automation and process control systems that demand robust, real-time communication, including but not limited to:

• Factory automation: Ensuring fast and synchronized data exchange among controllers, drives, and field devices over Ethernet-based industrial networks.
• Process industries: Facilitating reliable and time-sensitive communication in environments such as chemical plants, water treatment facilities, and refineries.
• Machine building: Supporting flexible automation topologies like ring, star, or linear configurations for machinery that require deterministic control and high network reliability.
• System integration: Offering clear guidelines for vendors and integrators to architect multi-vendor solutions using standardized fieldbus and Ethernet profiles.

The standard’s focus on performance metrics gives users measurable criteria for selecting and configuring network devices, matching specific application needs (e.g., cycle times, redundancy, and scalability).

Related Standards

For a comprehensive implementation, IEC 61784-2-20:2023 references several foundational standards and works in conjunction with other relevant specifications:

• IEC 61784-2 (all parts): Additional real-time fieldbus profiles based on Ethernet technologies.
• IEC 61784-2-0: General concepts and terminology for real-time fieldbus profiles.
• IEC 61784-1: Communication profile families for fieldbus systems.
• IEC 61158 (all parts): Fundamental specifications for industrial communication networks, including Data Link and Application Layer services and protocols.
• ISO/IEC/IEEE 8802-3: Ethernet standards, forming the communication layer foundation.
• IEEE 802.1Q, IEEE 802.1AS & IEEE 802.1AB: Standards covering VLANs, time synchronization for time-sensitive networking, and connectivity discovery.
• IETF RFCs (768, 791, 792, 793): Defining essential Internet protocols such as UDP, IP, ICMP, and TCP.

By adhering to these standards, CPF 20 enables interoperability, future-proofing, and adherence to global best practices in industrial Ethernet networking.

Keywords: IEC 61784-2-20, industrial networks, real-time Ethernet, fieldbus profiles, ISO/IEC/IEEE 8802-3, CPF 20, ADS-net, automation, process control, network performance indicators