IEC 61158-6-2:2014

Overview

IEC 61158-6-2:2014 is an international standard that specifies the application layer protocol for Type 2 elements in industrial communication networks using fieldbus technology. This third edition, issued by the International Electrotechnical Commission (IEC), updates the previous 2010 version with technical revisions aligned to the OSI Basic Reference Model (ISO/IEC 7498-1) and the OSI application layer structure (ISO/IEC 9545).

The standard focuses on defining the wire-representation of service primitives outlined in IEC 61158-5-2 and details the externally visible behavior during their transfer. It is essential for ensuring interoperability, clarity, and efficiency in industrial networks relying on Type 2 fieldbus application layers.

Key Topics

• Protocol Specification
  Defines the protocol framework for Type 2 application layer elements, covering service primitives, message formats, and connection management in industrial communication.

• Conformance to OSI Model
  The standard adheres strictly to the OSI application layer model, ensuring compatibility with international networking architectures.

• Service Primitive Wire-Representation
  Details the encoding and transfer behavior of primitives, critical for consistent communication across devices.

• Updates and Technical Revisions

  • Time Sync object definitions refined
  • Added "member" and object-specific services enhancing function coverage
  • Removed obsolete transport classes 4 to 6 to streamline protocol operations
  • Clarified transport header formats for better implementation
  • Updated Protocol Data Units (PDUs) for Connection Manager and other objects
  • Enhanced encapsulation abstract syntax and Data Link Layer (DLL) mapping protocols

• State Machine Structures
  Elaborates on protocol state machines including Application Relationship Protocol Machines (ARPMs) and DLL Mapping Protocol Machines for robust data link layer interactions.

• Data Types and Encapsulation
  Comprehensive data abstract syntax and compact encoding schemes defined for efficient data representation in network communication.

Applications

IEC 61158-6-2:2014 is vital for engineers, system integrators, and manufacturers implementing Type 2 fieldbus communication within industrial automation environments such as:

• Factory Automation
  Enables accurate and efficient communication among programmable logic controllers, sensors, and actuators.

• Process Control Systems
  Supports real-time data exchange and synchronization critical in chemical, oil & gas, and power generation industries.

• Industrial Network Design
  Provides the protocol foundation for designing reliable, interoperable fieldbus networks in harsh industrial settings.

• Device and Software Development
  Assists developers in creating compliant communication stacks and diagnostic tools for fieldbus-compatible devices.

• Quality of Service (QoS) Management
  Incorporates QoS features ensuring message prioritization and resource allocation for critical industrial data.

Related Standards

• IEC 61158-5-2
  Defines service primitives used within this standard, providing foundational elements for the application layer.

• ISO/IEC 7498-1
  The OSI Basic Reference Model guiding the layered network architecture used in this protocol specification.

• ISO/IEC 9545
  Specifies the OSI application layer structure referenced in defining behaviors and services.

• IEC 61158 Series
  Broader fieldbus specifications including physical layer and other application layer types.

• IEC 61784
  Profiles for fieldbus communication in industrial networks often implemented alongside IEC 61158 series.

Keywords: IEC 61158-6-2, Type 2 fieldbus, application layer protocol, industrial communication networks, OSI model, service primitives, fieldbus specifications, protocol state machines, industrial automation standards, DLL mapping, process control communication, industrial networking, Quality of Service (QoS), connection management, encapsulation syntax, protocol data units (PDUs).