IEC 61158-5-23:2023

Overview

IEC 61158-5-23:2023 - Industrial communication networks - Fieldbus specifications - Part 5-23: Application layer service definition - Type 23 elements - defines the application-layer services, data types and communication models used by Type 23 fieldbus systems in automation environments. The standard provides common elements for both time‑critical and non‑time‑critical messaging between application programs, and includes material specific to Type 23 fieldbus. Time‑critical is used to indicate actions required within a defined time window where failure to meet timing can risk equipment, plant or human safety.

Key topics and technical requirements

• Application layer service definitions (ASE): formal descriptions of services for cyclic and acyclic data exchange, management, synchronization, measurement and vendor-specific operations.
• Data types and fixed‑length types: standardized bitstring and numeric types used by application services.
• Communication models: cyclic (n:n and 1:n distributed shared memory), transient (client-server and push) models for deterministic and non‑deterministic messaging.
• AR (Application Relation) structures: channel and connection control, cyclic/acyclic transmission parameters, synchronous triggers and measurement transmission.
• Service parameters and conformance: detailed service parameter tables (read, write, set, reset, run/stop, memory access, attribute get/set, time sync, SLMP, etc.) that specify required behavior for interoperability.
• Types C, F and T: distinct ASE and AR structures and behaviors described for multiple FAL (Fieldbus Application Layer) types to cover different usage scenarios.

Applications and who uses this standard

IEC 61158-5-23:2023 is intended for:

• Automation and control engineers designing deterministic fieldbus communication for PLCs, I/O devices and motion systems.
• Device and sensor manufacturers implementing Type 23 fieldbus stacks and ensuring application-layer interoperability.
• System integrators and plant operators selecting communication technologies for factory automation, process control and safety‑critical installations.
• Standards authors and test laboratories developing conformance tests and certification for fieldbus products.

Practical applications include factory floor data exchange, coordinated motion control, time‑synchronized measurements, vendor command transport and management functions in industrial networks where timing guarantees or structured data services are required.

Related standards

• IEC 61158 family (Fieldbus specifications) - other Part 5 documents for different Type elements and FAL definitions.
• ISO/IEC OSI references (ISO/IEC 7498‑1, ISO/IEC 8822) referenced for terminology and service conventions.

Keywords: IEC 61158-5-23:2023, Type 23, fieldbus, application layer service, industrial communication, time-critical messaging, cyclic communication, ASE, AR, automation network.