IEC 61158-5-7:2007

Overview

IEC 61158-5-7:2007 - "Industrial communication networks - Fieldbus specifications - Part 5-7: Application layer service definition - Type 7 elements" is an international standard that specifies the application layer services for Type 7 fieldbus implementations. It defines the services provided to the FAL (Fieldbus Application Layer) user and the interface to Systems Management, in conformance with the OSI Basic Reference Model (ISO/IEC 7498) and OSI Application Layer Structure (ISO/IEC 9545). This edition (2007) is an editorial revision of the IEC 61158-5 subseries, replacing IEC 61158-5:2003 and reflecting structural changes across the part‑5 subparts (5-2, 5-3, …). Keywords: IEC 61158-5-7, fieldbus, application layer, industrial communication networks, Type 7.

Key Topics

The standard covers detailed technical elements and service definitions for implementing the fieldbus application layer (FAL). Key topics and requirements include:

• FAL service definitions: Formal procedures and parameters for Read/Write/Update services and list operations (A_Read, A_Write, A_Readlist, etc.).
• Data type ASE: Formal definition and structure of application‑layer data types and object models.
• Communication model: ASEs (Application Service Elements) and ARs (Application References) organisation and usage.
• State machines and service procedures: State charts and sequence diagrams for associate/release/abort, data transfer and program invocation services.
• Timing and consistency mechanisms: Promptness and refreshment mechanisms (asynchronous, synchronous, punctual), resynchronisation, temporal and spatial consistency handling.
• Systems Management interface: Domain management, upload/download sequences, program invocation and MMS-related environment management.
• Conformance and interoperability: Definitions necessary for implementers to achieve consistent behaviour across Type 7 fieldbus devices.

Applications

IEC 61158-5-7 is primarily used by professionals working on industrial communication and automation:

• Device manufacturers building fieldbus-enabled I/O modules, controllers, and field devices that implement the Type 7 application layer.
• System integrators and automation engineers ensuring correct application‑layer behaviour, data consistency, and timing in control systems.
• Firmware and protocol stack developers implementing ASEs, state machines, and service procedures.
• Test labs and certification bodies performing conformance and interoperability testing for fieldbus products.
• Plant designers applying fieldbus solutions in process control, discrete manufacturing, and distributed automation.

Related Standards

• IEC 61158 series (Fieldbus specifications) - other Part 5 subparts (5-2, 5-3, …) for different fieldbus types.
• ISO/IEC 7498 (OSI Basic Reference Model) and ISO/IEC 9545 (OSI Application Layer Structure) - referenced OSI models used as a basis for FAL definitions.

This standard is essential when implementing or validating the application layer service definition for Type 7 fieldbus solutions in industrial communication networks.