Overview
IEC 61158-3-2:2014 is an international standard that specifies the data‑link layer services for Type 2 fieldbus protocols used in industrial communication networks. It defines the services presented to the Type 2 application layer at the boundary between the application layer and data‑link layer, and the services between the data‑link layer and systems management. The Type 2 DL‑service includes both connection‑mode and connectionless‑mode subsets (aligned with ISO/IEC 8886). This edition consolidates the 2014 publication and its 2019 amendment (editorial updates and corrections such as fixed tag references).
Key topics and technical requirements
- Data‑link layer service model: Definitions of DLSAPs, addresses, queues and DLCEPs that structure communication between DLS‑users.
- Transfer modes: Clear distinction and service primitives for connection‑mode (reliable, sequenced) and connectionless‑mode (unconfirmed, multicast/peer) data transfer.
- Service primitives and sequences: Time‑sequence diagrams and primitive sets governing request/indication/confirm flows for transfers and management functions.
- Queue maintenance and tag filtering: Mechanisms for message queuing, priority handling, and fixed tag / tag filtering services for selective delivery.
- DL‑management (DLM) services: Management primitives for link synchronization, synchronized parameter change, event reporting, bad FCS reporting, moderator control, power‑up / online behavior and listen‑only modes.
- Time distribution: Parameters and quality metrics for distributing time across the network to support synchronized operation.
- Conformance and interoperability: Normative references and conformance clauses to ensure consistent implementation across devices.
Applications and who uses it
IEC 61158-3-2 is targeted at professionals implementing, testing or integrating fieldbus and industrial Ethernet systems:
- Industrial automation engineers designing deterministic communications for process and discrete manufacturing.
- Device manufacturers (PLCs, I/O modules, gateways) implementing Type 2 data‑link services.
- System integrators and control system architects ensuring multi‑vendor interoperability.
- Test labs and certification bodies validating conformance to fieldbus service semantics.
Typical applications include real‑time control loops, distributed I/O networks, synchronized operations, and systems requiring both multicast and point‑to‑point messaging.
Related standards
- IEC 61158 (other parts) - Fieldbus specification family.
- IEC 61784‑1 / IEC 61784‑2 - Combinations and profiles of protocol types.
- ISO/IEC 8886 - Source for connection/connectionless service definitions referenced by Type 2 DL‑service.
Keywords: IEC 61158-3-2, fieldbus, data‑link layer, Type 2, DL‑service, connection‑mode, connectionless, industrial communication, link synchronization, time distribution, queue maintenance.