IEC 61158-3-8:2007

Overview

IEC 61158-3-8:2007 - part of the IEC 61158 fieldbus specifications - defines the abstract, externally visible data‑link layer service for Type 8 fieldbus systems. It specifies the primitives (request/confirm, indication/response), the parameters associated with each primitive, and the valid sequences and interactions between primitives. The standard targets time‑critical messaging in industrial automation and supplements the OSI Basic Reference Model to guide development of data‑link protocols used in safety‑ and time‑sensitive control systems.

Key Topics

• Scope and purpose
  • Conceptual definition of services between the Type 8 application layer and the data‑link layer, and between data‑link layer and systems management.
  • Emphasis on time‑windowed, time‑critical communications where timing guarantees are required.
• Service elements
  • Primitive actions and events, their parameters and parameter formats, and valid primitive sequences.
  • Examples of documented services/primitives in the part: Put Buffer / Get Buffer, Normal data transfer, Reset, Event, Set Value / Get Value, Get Current/Active Configuration, Set Active Configuration.
• Connection modes
  • Definition of connection‑mode data‑link services, DL‑connection end points (DLCEPs), addressing (DLSAPs, DL-addresses) and group addressing relationships.
• Management and conformance
  • DL‑management service facilities and detailed interactions.
  • The document is an abstract service definition - conformance is achieved by implementing a corresponding data‑link protocol that fulfils these services (the standard itself is not a runtime API).
• Normative references
  • Built on ISO/IEC 7498‑1, 7498‑3 and ISO/IEC 10731; aligns with other IEC 61158 parts and IEC/TR 61158‑1.

Applications

• Used by protocol designers and fieldbus implementers to define Type 8 data‑link protocols for time‑critical industrial systems.
• Guidance for device manufacturers, system integrators, and automation engineers developing or integrating controllers, I/O devices, and gateways requiring deterministic, time‑bounded communications.
• Useful when migrating legacy industrial protocols to modern fieldbus types or when developing DL‑programming interfaces (note: implementers must still define concrete parameter sizes, octet ordering and primitive correlation).

Related Standards

• IEC 61158 series (other Part 3‑x elements for different Types)
• IEC 61784 (combinations of protocol types and profiles)
• IEC/TR 61158‑1 (fieldbus reference model)
• ISO/IEC 7498‑1, 7498‑3, ISO/IEC 10731

IEC 61158-3-8 is an editorially revised, abstract service definition for Type 8 fieldbus data‑link layers aimed at ensuring interoperable, time‑critical industrial communications.