IEC 61158-5-17:2007

Overview

IEC 61158-5-17:2007 - "Industrial communication networks - Fieldbus specifications - Part 5-17: Application layer service definition - Type 17 elements" defines the abstract, externally visible services of the Fieldbus Application Layer (FAL) for Type 17 fieldbus systems. Published by the IEC in 2007, this part describes how user programs access the fieldbus environment (the FAL “window”), supporting both time‑critical and non‑time‑critical messaging between automation application programs. The standard specifies the object model, service primitives, parameters, and valid sequences for application‑level communication and system management.

Key topics

• FAL architecture and service model: Abstract model of Application Entities (AEs), Application Service Elements (ASEs) and Layer Management Entity (LME).
• ASE types: Variable ASE, Event ASE, Load Region ASE, Function Invocation ASE, Time ASE, Network Management ASE, Application Relationship ASE - defining the classes of application resources and services they expose.
• Application relationships (AR/AREP): AR roles and examples (point‑to‑point, multipoint, publisher/subscriber, confirmed/unconfirmed) for conveying APDUs between application processes.
• Time‑critical messaging: Definitions and handling of operations where meeting a time window is essential to avoid application or safety failures.
• Service primitives and parameters: Read/write, event notification, download/upload, start/stop/resume, network time and status services - with associated parameters and sequencing rules.
• Conformance and interoperability: Abstract service definitions aligned with the OSI model (ISO/IEC 7498) and OSI Application Layer structure (ISO/IEC 9545).

Applications

• Industrial control and automation systems requiring standardized application‑layer communications
• Real‑time process control, motion control, and safety‑critical systems where time‑window guarantees are required
• Device and gateway vendors implementing Type 17 fieldbus stacks
• System integrators and network architects designing interoperable fieldbus networks with predictable application behavior

Who uses this standard

• Automation engineers and designers specifying fieldbus application behavior
• Embedded and firmware developers implementing FAL ASEs and AR protocols
• Device manufacturers conforming to IEC 61158 family for interoperability
• Safety and systems management teams needing formalized time‑critical messaging services

Related standards

• IEC 61158 (other parts) - Fieldbus specifications series
• IEC/TR 61158‑1 - Fieldbus reference (three‑layer) model
• IEC 61784 - Profiles and permitted protocol combinations
• ISO/IEC 7498 and ISO/IEC 9545 - OSI model references

IEC 61158-5-17:2007 provides the essential, vendor‑neutral application‑layer service definitions and object models needed to build interoperable, reliable, and time‑aware industrial communication solutions based on Type 17 fieldbus technology.