IEC 61158-4-25:2019

Overview

IEC 61158-4-25:2019 is an international standard developed by the International Electrotechnical Commission (IEC), focusing on industrial communication networks, specifically Fieldbus systems. This part of the IEC 61158 series defines the data-link layer protocol specification for Type 25 elements, providing essential procedures for timely and reliable data and control information transfer. The standard plays a key role in ensuring seamless communication and interoperability among sensors, effectors, and other automation devices in open and heterogeneous industrial environments.

Utilizing this standard alongside others in the IEC 61158 family allows previously incompatible systems to work together, supporting the integration of diverse automation solutions based on OSI (Open Systems Interconnection) and Fieldbus reference models.

Key Topics

• Data-link layer protocol: Defines procedures and rules that enable the timely exchange of data and control information among peer data-link entities (DLEs) and between data-link service (DLS) providers and users.
• Cyclic and acyclic communication: Supports both periodic (cyclic) and on-demand (acyclic) data transmissions, catering to diverse industrial requirements for both real-time and non-real-time communications.
• Time-critical messaging: Enables deterministic and synchronized communications suitable for industrial automation, with cyclic intervals as short as one millisecond.
• Prioritized access: Establishes communication opportunities by prioritizing time-critical transmissions while allowing for non-time-critical data without negatively impacting system responsiveness.
• Medium access control (MAC): Incorporates procedures based on ISO/IEC/IEEE 8802-3 (Ethernet) for robust media management, including node addition or removal during live operation.
• Structured data units: Specifies the format and encoding of Fieldbus Data-Link Protocol Data Units (DLPDUs), which are the foundation for reliable data exchanges in distributed automation systems.
• Open systems compatibility: Facilitates the interoperation of automation devices from different manufacturers within open systems environments.

Applications

IEC 61158-4-25:2019 is used extensively in:

• Process automation: Enables real-time exchange of sensor and actuator data in manufacturing and process industries.
• Factory automation: Supports detectors, controllers, and effectors in robotics, assembly lines, and production systems.
• Interoperability in complex networks: Supports seamless communication in multi-vendor environments by standardizing the data-link layer protocol for Type 25 fieldbus networks.
• System integration: Aids system designers and implementers in creating compatible equipment, as well as ensuring proper vendor equipment sourcing and acceptance testing.
• Conformance assessment: Provides the baseline for specifying requirements that systems must meet to be deemed compliant with this protocol, supporting procurement and integration quality assurance activities.

Related Standards

• IEC 61158 series: Covers various Fieldbus specification types and application layers for industrial communication networks.
• IEC 61784-1 & IEC 61784-2: Offer profiles for practical installation and system integration of Fieldbus-based control systems in industrial environments.
• ISO/IEC 7498-1 & ISO/IEC 7498-3: Define the basic model of OSI and its conventions for naming and addressing, forming the foundational reference architecture.
• ISO/IEC/IEEE 8802-3 (Ethernet): Basis for medium access control used in Fieldbus implementations.
• IEEE 802.1D and IEEE 802.1Q: Address MAC bridges and VLAN operation, enhancing the priority and traffic management mechanisms supported in Fieldbus networks.

Practical Value

IEC 61158-4-25:2019 enables businesses and industries to build robust, interoperable, and future-proof automation infrastructures. By addressing the stringent requirements of time-critical communication, providing mechanisms for integrating devices from multiple vendors, and supporting both cyclic and acyclic data exchanges, this standard is essential for any modern industrial communication network seeking reliability, flexibility, and adherence to international best practices.