IEC 61131-2:2017

Overview

IEC 61131-2:2017 is an international standard published by the International Electrotechnical Commission (IEC) that defines equipment requirements and testing procedures for programmable controllers used in industrial-process measurement and control. This fourth edition, a technical revision of the 2007 third edition, focuses on ensuring the functional performance and electromagnetic compatibility (EMC) of industrial control equipment such as Programmable Logic Controllers (PLCs), Programmable Automation Controllers (PACs), and their associated peripherals.

The standard addresses devices primarily intended for controlling and commanding machines and automated manufacturing processes, including discrete, batch, and continuous control systems. IEC 61131-2:2017 establishes requirements for environmental conditions, functional inputs/outputs, communication capabilities, and EMC performance, ensuring interoperability and reliability in industrial automation environments.

Key Topics

• Scope and Compliance
  The standard applies to industrial control products focused on controlling manufacturing processes. Compliance involves passing detailed type tests and meeting specified operational criteria across a range of environments.

• Functional Equipment Requirements

  • Power input and memory backup requirements
  • Digital I/O specifications, including positive and negative logic inputs and outputs
  • Analog I/O compatibility, including support for HART® communication
  • Communication interfaces and remote input/output station (RIOS) integration
  • Self-test and diagnostic capabilities

• Environmental and Mechanical Conditions

  • Operating temperature ranges and relative humidity tolerance
  • Altitude derating considerations for temperature
  • Resistance to vibrations, mechanical shock, and free falls
  • Transport and storage conditions ensuring device integrity

• Electromagnetic Compatibility (EMC)

  • Emission limits and immunity levels, including radio-frequency immunity from 2.7 GHz to 6 GHz
  • Voltage dips and interruption resilience at power ports
  • EMC installation guidelines to minimize interference and ensure operational stability

• Marking and Documentation
  Requirements for clear manufacturer markings and detailed information to support installation, operation, compliance verification, and maintenance.

Applications

IEC 61131-2:2017 is critical for manufacturers and users of industrial automation equipment such as PLCs and PACs used in:

• Automated Manufacturing Plants
  Ensuring reliable control of machinery and process automation lines across diverse manufacturing sectors.

• Process Industry Automation
  Controlling batch, continuous, or discrete processes in industries like chemical, pharmaceutical, and food processing.

• Machine Control Systems
  Integration with automated machines requiring precise digital and analog input/output controls, diagnostics, and communication.

• Safety-Critical Environments
  Though safety requirements are referenced to IEC 61010-2-201, IEC 61131-2 ensures correct functional behavior and EMC performance critical to secure process operations.

Adhering to this standard helps optimize device reliability, interoperability, and regulatory compliance-keys to efficient and safe industrial control systems.

Related Standards

• IEC 61131-1 – General information and programming languages for programmable controllers
• IEC 61010-2-201 – Safety requirements specific to control equipment
• IEC 61131-9 – Distributed Clocks and Synchronization Interface (supporting discrete channel compatibility)
• HART® Communication Protocol – Ensured compatibility with analog inputs/outputs in IEC 61131-2 for remote device management
• EMC Standards such as CISPR and IEC 61000 series – Providing broader guidelines on electromagnetic emission and immunity testing

Keywords: IEC 61131-2:2017, programmable controllers standard, industrial process control, PLC requirements, PAC testing, EMC compliance, digital and analog I/O, industrial automation standards, IEC programmable controller equipment, industrial control system reliability, automated manufacturing process control