IEC 61499

IEC 61499 is an international standard for distributed control systems. It defines a domain-specific modeling language for designing and implementing distributed industrial process measurement and control systems. It builds upon the IEC 61131-3 standard for programmable logic controllers (PLCs), but extends its capabilities to address the challenges of distributed, modular, and reconfigurable control applications.

The standard promotes a function block-oriented approach, where control logic is encapsulated within reusable function blocks. These function blocks can then be interconnected and distributed across a network of devices, enabling modularity, reusability, and scalability. Key concepts within IEC 61499 include:

• Function Blocks: The fundamental building blocks of an IEC 61499 application. They encapsulate control logic, input/output variables, and execution control elements. Different types of function blocks exist, including basic function blocks (BFBs) which contain algorithms coded in a variety of languages, and composite function blocks (CFBs) which are composed of other function blocks.

• Event-Driven Execution: Function blocks are executed in response to events, allowing for asynchronous and reactive behavior. Events trigger the execution of algorithms within the function blocks.

• Interface: Defines the inputs and outputs of a function block, including both data variables and event inputs/outputs.

• Execution Control Chart (ECC): A state-machine-like diagram that defines the execution order of algorithms within a function block in response to different event inputs.

• Management Model: Provides a framework for managing and configuring distributed applications, including device management, resource allocation, and communication management.

• System Configuration: The process of defining the network topology, device capabilities, and function block distribution across the network.

IEC 61499 aims to improve interoperability and portability of control applications by providing a standardized modeling language and execution environment. It also facilitates the development of more flexible and adaptable control systems that can be easily reconfigured and maintained.

The standard is used in various industries, including manufacturing, process control, and robotics, to develop distributed and intelligent control solutions. It addresses challenges associated with increasing complexity and decentralization in modern industrial automation systems.