IEC 61804-2:2018

Overview

IEC 61804-2:2018 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies the concept of Function Blocks (FB) for process control and Electronic Device Description Language (EDDL). This third edition supersedes the 2006 version and merges parts of the now-withdrawn IEC 61804-1 standard. It focuses on harmonizing essential elements related to device modeling, function block conceptual specifications, and integration technologies applicable in process automation industries.

The standard defines a structured device model composed of interoperable function blocks designed for measurement, actuation, and processing tasks. Its purpose is to enable robust, flexible, and innovation-friendly control solutions while accommodating sector-specific specialization. Moreover, IEC 61804-2 supports integration with EDDL, facilitating detailed electronic descriptions of real-world devices through engineering lifecycle tools.

Key Topics

• Function Block (FB) Concept and Device Model
  The standard clarifies the architecture of an IEC 61804-2 compliant device, outlining the hierarchical structure of FBs that represent functional components of automation equipment. This includes input/output functions, calculation and control blocks, and technology-specific blocks such as temperature or pressure controllers.

• Measurement, Actuation, and Processing Blocks
  It encompasses general specifications for FBs related to sensor data acquisition (measurement channels), output commands (actuation channels), and various signal and control processing functionalities ensuring consistent behavior and integration.

• Electronic Device Description Language (EDDL) Integration
  IEC 61804-2 describes how EDDL technology fits into the device model. EDDL enables precise electronic representation of device capabilities and parameters, supporting configuration, diagnostics, and system integration over the engineering lifecycle.

• Technical Enhancements in Edition 3
  Notable updates include:

  • Introduction of command communication mapping to support enhanced device command interaction.
  • Relocation and refinement of compatibility level definitions to improve clarity and usability.
  • Addition of a proxy concept to facilitate indirect access and integration of function blocks in distributed control environments.

Applications

IEC 61804-2:2018 plays a critical role in process automation and industrial control systems by providing a standardized framework for device interoperability and control logic modularization. Key application areas include:

• Process Control Systems
  Enhances the design of distributed control systems (DCS) through reusable and interoperable function blocks, enabling efficient development, deployment, and maintenance of control strategies.

• Industrial Device Configuration and Integration
  Facilitates seamless integration of sensors, actuators, and controllers across diverse industrial sectors, enhancing compatibility between devices from different manufacturers.

• Engineering Lifecycle Support
  Supports device configuration, testing, commissioning, and diagnostics through standardized EDDL descriptions, extending device management capabilities throughout its operational life.

• Automation Innovation and Specialization
  The framework avoids restricting innovation by providing generalized block definitions while enabling sector-specific customization, supporting evolving industrial automation needs.

Related Standards

• IEC 61804-1 (withdrawn)
  Earlier parts of the function block specification previously incorporated into IEC 61804-2.

• IEC 61499
  Defines a reference model for distributed control based on function blocks; IEC 61804-2 relates to this by specifying mappings and interoperable architectures.

• IEC 61131
  Covers programmable logic controller (PLC) programming languages and may be complementary for implementation of control logic.

• IEC 61784
  Standardizes fieldbus communication protocols which are often used alongside function block-based devices.

• EDD and EDDL Standards
  Related standards governing electronic device description languages that facilitate device configuration and lifecycle management.

IEC 61804-2:2018 is essential for engineers and system integrators aiming to implement advanced, interoperable process control solutions with standardized function blocks and device descriptions. Its emphasis on harmonization and modular design ensures improved compatibility, lifecycle management, and future-proof automation architectures.