IEC 61158-5-9:2014

Overview

IEC 61158-5-9:2014 - "Industrial communication networks – Fieldbus specifications – Part 5-9: Application layer service definition – Type 9 elements" defines the application-layer service model for a specific fieldbus element set (Type 9). The standard specifies the services available to the Fieldbus Application Layer (FAL) user at the user/application boundary and the Services Management (SM) interaction at the application/SM boundary. It aligns the IEC fieldbus application layer structure and services with the OSI Basic Reference Model (ISO/IEC 7498‑1) and the OSI application layer structure (ISO/IEC 9545). This 2014 edition supersedes the 2007 edition and incorporates a technical correction to the download state machine event service.

Key topics and technical requirements

• Application layer services: Defines what services are offered to FAL users at the application boundary for Type 9 elements (service semantics, roles and expected behaviors).
• Systems Management (SM) interface: Specifies the interactions and service points between the application layer and Systems Management for configuration, diagnostics and lifecycle operations.
• Conformance to OSI: Service definitions and layer structure are specified in conformance with ISO/IEC 7498‑1 and ISO/IEC 9545, ensuring interoperability and consistent layering.
• Type 9 element set: Describes the specific set of application-layer elements and their service semantics for this Type, as defined within IEC 61158 parts.
• Technical revision: Contains a correction to the download state machine event service, clarifying expected state transitions and event behavior during device or firmware download processes.

Note: IEC 61158-5-9 defines service-level behavior and interfaces rather than low-level physical signalling or exact wire-level encodings (these are covered in other parts of the IEC 61158 / 61784 series).

Applications and who uses it

This standard is relevant for professionals and organizations involved in industrial communication and fieldbus technology:

• Device and fieldbus protocol designers: Implement application-layer services consistent with Type 9 element semantics.
• Industrial control system (ICS) manufacturers: Ensure device firmware and application logic conform to FAL and SM interfaces.
• System integrators and automation engineers: Use the service definitions to design interoperable control architectures, integration with PLCs, RTUs and HMIs.
• Test and certification labs: Validate conformance to application-layer behaviors and download state machine semantics.
• Maintenance and operations teams: Rely on standardized SM and application services for diagnostics, configuration and safe firmware download procedures.

Typical application domains include factory automation, process control, utilities, and distributed field device networks where standardized fieldbus application services improve interoperability and manageability.

Related standards

• IEC 61158 (fieldbus series) - other parts covering lower layers and protocol types
• ISO/IEC 7498‑1 - OSI Basic Reference Model
• ISO/IEC 9545 - OSI Application Layer structure

Keywords: IEC 61158-5-9, fieldbus application layer, Type 9 elements, industrial communication networks, application layer service definition, OSI model, Systems Management, download state machine.