Overview
IEC 61158-4-17:2007 - Industrial communication networks - Fieldbus specifications - Part 4-17: Data-link layer protocol specification - Type 17 elements - specifies the data-link layer for Type 17 fieldbus systems used in industrial automation. Edition 1.0 (2007-12) defines the procedures, message formats and services that provide time‑critical messaging communications between peer data‑link entities (DLEs). This part is one element of the IEC 61158 fieldbus series and replaces earlier editions (IEC 61158-4:2003 and IEC/PAS 62405). The document describes DLPDU structure, protocol architecture, scheduling, redundancy and security/authentication features for deterministic communication in automation environments.
Key Topics
- Data‑link layer architecture: role within the fieldbus/OSI reference model and how the DLL uses physical‑layer services to deliver deterministic messaging.
- Protocol characteristics: support for cyclic asynchronous and synchronous (scheduled) message transfer to meet strict timing requirements.
- DLPDU structure and encoding: common header and body formats for Data‑Link Protocol Data Units (DLPDUs) and defined PDU types/subtypes.
- Services and procedures: unacknowledged and acknowledged unitdata transfer (UUS, AUS), acknowledged sequences (ASS), multipoint services (MUS, MSS) and their procedure tables.
- Local parameters & resources: configuration ranges and parameters for network structure, real‑time transfer, scheduling and security.
- Transmission scheduling & redundancy: support for scheduled access, deterministic cycles and redundancy mechanisms for high availability.
- Security / authentication: DLPDU authentication and related security elements to protect control communications.
- Conformance & applicability: guidelines for implementors, testing bodies and system integrators; notes on intellectual property and patent declarations (e.g., PCT filings noted by the standard).
Applications & Who Uses It
IEC 61158-4-17 is intended for:
- Automation device manufacturers (PLCs, I/O modules, sensors, actuators) implementing a Type 17 data‑link layer.
- System integrators and control engineers designing deterministic fieldbus networks for process and factory automation.
- Test labs and procurement teams using the specification for compliance testing and equipment selection.
- OEMs and safety/availability engineers deploying time‑critical, redundant or secure industrial communication systems.
Typical use cases include real‑time control loops, synchronized I/O polling, deterministic messaging for safety or process control, and high‑availability network topologies.
Related Standards
- IEC 61158 series (fieldbus specifications)
- IEC/TR 61158‑1 (fieldbus reference model)
- IEC 61784 (profiles and permitted type combinations)
- Note: This part cancels/replaces IEC 61158‑4:2003 and IEC/PAS 62405; users should check the IEC webstore for the latest editions and any corrigenda.
Keywords: IEC 61158-4-17, data-link layer, fieldbus, Type 17, industrial communication networks, time-critical messaging, DLPDU, scheduling, redundancy, real-time automation.
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