IEC 61158-4-18:2010

Overview

IEC 61158-4-18:2010 is an international standard from the International Electrotechnical Commission (IEC) that addresses data-link layer protocol specifications for industrial communication networks, specifically for fieldbus Type 18 elements. This standard defines the protocol procedures used by devices in automation environments to ensure reliable, time-critical data exchanges within the data-link layer. It supports both synchronously-starting cyclic communication based on pre-set schedules and cyclic or acyclic asynchronous communication, providing flexibility for various industrial requirements.

This second edition offers technical revisions over its predecessor, including editorial enhancements and the addition of cyclic data segmenting, which further refines how industrial automation components communicate in deterministic and time-sensitive contexts. The standard supports open systems interconnection (OSI) principles to promote interoperability among diverse automation equipment and systems.

Key Topics

• Data-link Layer Protocol Specification: Detailed procedures for time-critical message exchange between fieldbus devices at the data-link level.
• Time-Critical Communications: Mechanisms for deterministic and synchronized data transfer, ensuring timely responses for automation control systems.
• Cyclic and Acyclic Communication: Methods to provide both scheduled (cyclic) and on-demand (acyclic) data transfer, supporting a wide range of process automation requirements.
• Master/Slave and Packed/Polled Classes: Specifies four classes of Data Link Entities (DLEs): master-polled, slave-polled, master-packed, and slave-packed, each suited to particular network roles and response strategies.
• HDLC-based Transmission: Utilizes a subset of ISO/IEC 13239 HDLC for robust and reliable data-link framing and error detection.
• Implementation Profiles: Profiles summarize device capabilities and compatibility for different types of time-critical communications, aiding selection and integration decisions.
• Support for OSI and Fieldbus Reference Models: Enables integration and interworking among components from different vendors by aligning with widely accepted reference architectures.

Applications

IEC 61158-4-18:2010 is pivotal in the industrial automation sector, where precise, real-time communication between controllers, sensors, actuators, and other devices is essential. Its applications include:

• Factory Automation: Facilitates deterministic networking among PLCs, drives, and I/O modules on factory floors where timing is critical.
• Process Control: Used in plants where communicating process variables quickly and reliably is vital to performance and safety.
• Distributed Control Systems (DCS): Ensures synchronized and prioritized data transfer between distributed nodes in complex industrial systems.
• Machine-to-Machine (M2M) Communication: Provides a structured protocol enabling intelligent machines to coordinate operations efficiently.
• Integration of Heterogeneous Systems: Adheres to open systems principles, supporting integration of devices from multiple manufacturers without proprietary constraints.

The standard benefits manufacturers, integrators, and end users seeking to design, implement, and maintain highly reliable industrial communication networks with strict timing and interoperability requirements.

Related Standards

Several international standards complement IEC 61158-4-18 for comprehensive industrial networking solutions:

• IEC 61158 Series: Widely recognized as the foundational family for fieldbus communication, specifying physical, data-link, and application layers for industrial networks.
• IEC 61158-1: Overview and guidance for fieldbus reference models.
• IEC 61158-6 (Application Layer): Defines application layer services and protocols for various fieldbus types.
• ISO/IEC 13239: High-level Data Link Control procedures, referenced for HDLC framing within the data-link protocol.
• ISO/IEC 7498-1 & ISO/IEC 7498-3: OSI Reference Model and naming/addressing conventions for open system interconnection.
• IEC 61784: Profiles for communication networks in industrial facilities.

Implementing IEC 61158-4-18:2010 ensures robust, efficient, and interoperable data-link layer communications in modern industrial automation systems.