December 2025: New Standard Enhances Programmable Controller Reliability in Manufacturing

In December 2025, the realm of manufacturing engineering saw a significant leap forward with the release of the EN IEC 61131-2:2025 standard. Covering programmable controllers and associated equipment, this standard provides refined equipment requirements and rigorous testing procedures, essential for reliable, safe, and compliant industrial automation. For industry professionals dedicated to precision, productivity, and regulatory compliance, understanding these updates is vital. This article delves into what’s new, why it matters, and how your organization can benefit from adopting this updated standard.

Overview / Introduction

Manufacturing engineering is the backbone of industrial productivity, driving innovations in control, automation, and process optimization. Standards in this sector ensure operational consistency, equipment interoperability, product quality, and—most importantly—safety and reliability. Programmable controllers are at the heart of process control, powering everything from assembly lines to process plants.

Industry professionals, including compliance officers, engineers, and procurement specialists, rely on up-to-date standards to mitigate risk, future-proof investments, and streamline certification. This article offers a detailed analysis of the EN IEC 61131-2:2025 standard—unpacking its scope, key requirements, notable changes, and practical implications for manufacturers and automation providers.

Detailed Standards Coverage

EN IEC 61131-2:2025 – Equipment Requirements and Tests for Programmable Controllers

Industrial-process measurement and control – Programmable controllers – Part 2: Equipment requirements and tests

The new edition of EN IEC 61131-2:2025 updates the benchmark for functional and electromagnetic compatibility (EMC) requirements, as well as related testing for programmable controllers and their peripherals. This includes not only traditional PLCs (Programmable Logic Controllers) but also Programmable Automation Controllers (PACs), industrial PCs, HMIs, distributed control systems (DCS), and remote I/O devices—critical elements in automated manufacturing environments.

What the Standard Covers

EN IEC 61131-2:2025 sets forth:

• Functional requirements for programmable controllers and associated equipment
• EMC requirements and test procedures
• Specifications for equipment used in industrial process measurement and control, including interfaces, digital and analog I/Os, power supplies, and communication modules
• Guidelines for verifying compliance through type and performance testing

This standard is globally relevant, providing harmonized criteria across diverse manufacturing environments and ensuring compatibility, reliability, and system safety.

Key Requirements and Specifications

The standard details:

• Robust equipment performance under varied conditions (temperature, humidity, altitude, shock, vibration)
• Comprehensive EMC testing (electromagnetic immunity and emissions)
• New test procedures for negative logic digital I/Os, including Type 3-d digital inputs
• Power supply resilience (including voltage interruptions, surges, and transient disturbances)
• Self-test and diagnostic requirements for control systems
• Marking, documentation, and manufacturer information obligations

Who Needs to Comply?

EN IEC 61131-2:2025 applies to any organization designing, manufacturing, integrating, or specifying:

• Programmable controllers (PLCs, PACs)
• Remote I/O units and network interfaces
• Industrial PCs, HMIs, programming tools
• Peripherals used in automated manufacturing, process industries, or machinery control

Target sectors span automotive, food & beverage, chemical, pharmaceutical, general manufacturing, and beyond.

Practical Implications for Implementation

• Enhanced equipment selection and procurement criteria for compliance
• Updated engineering practices to incorporate revised EMC and performance tests
• Streamlined certification processes aligned with international best practices
• Improved reliability and maintainability of process control hardware

Notable Changes from Previous Editions

This fourth edition introduces substantial technical updates:

• Removal of direct safety requirements (now addressed via IEC 61010-2-201)
• Introduction of negative logic digital inputs/outputs
• Addition of the new Type 3-d digital input
• Extended radio-frequency immunity (now up to 6 GHz)
• Clarified and expanded temperature cycling, type testing, and environmental limits
• Deprecation of legacy technologies and a more logical reorganization of clauses for improved usability

Key highlights:

• Comprehensive EMC and functional type testing aligned with the latest industrial needs
• Broader support for next-generation automation hardware
• Improved test methods and clearer documentation for manufacturers

Access the full standard:View EN IEC 61131-2:2025 on iTeh Standards

Industry Impact & Compliance

How the Updated Standard Affects Manufacturing Businesses

For manufacturers, system integrators, and automation vendors, compliance with EN IEC 61131-2:2025 is more than a regulatory checkbox—it’s a strategic necessity. Integrating the latest equipment requirements and EMC performance criteria:

• Reduces the risk of equipment failure and downtime during operation
• Ensures globally recognized certification, simplifying international trade and regulatory filings
• Protects against costly field issues related to EMI, electrostatic discharge, or environmental extremes

Compliance Considerations and Timelines

• Manufacturers supplying control equipment or systems should immediately align design and test procedures to the new requirements
• National and regional implementation deadlines may apply, with conflicting standards to be withdrawn by December 2030 within Europe
• Supply chain partners and OEMs should update technical specifications and procurement documents to reference EN IEC 61131-2:2025

Benefits of Early Adoption

• Competitive differentiation with more robust, reliable products
• Streamlined global market access and reduced time-to-certification
• Increased customer confidence and enhanced quality image

Risks of non-compliance include regulatory penalties, export restrictions, increased warranty costs, and reputational harm resulting from product recalls or failures in the field.

Technical Insights

Common Technical Requirements Across the Standard

Key technical pillars include:

• Service Environments: Controllers must perform reliably across a wide range of temperatures (from -40°C to 70°C) and humidity levels (up to 100%), depending on type
• Mechanical Durability: Equipment must survive vibration, shock, and rough handling tests
• Power Robustness: Type testing for voltage surges, transient interruptions, supply variations, and backup duration
• Digital and Analog I/O Performance: Clear definitions for logic types, impedance ranges, overload capacity, and compatibility with modern protocols (including HART and SDCI)
• EMC Immunity: Testing according to IEC 61000 series for electrostatic discharge, radiated and conducted disturbances, surges, voltage dips/interruptions, and power frequency magnetic fields

Implementation Best Practices

• Follow Manufacturer Guidance: All tests should be performed in line with supplier installation and configuration recommendations
• Document All Test Results: Full traceability and reproducibility are required for claims of compliance
• Adopt Modular Testing: For complex systems, test representative configurations that cover all module/port types
• Focus on Type and Withstand Testing: Test the boundaries of performance, not just day-to-day functionality
• Use Internationally Recognized Methods: Refer to the latest referenced IEC and ISO standards for environmental, mechanical, and EMC testing

Testing and Certification Considerations

• Use independent, accredited labs for EMC and functional testing where possible
• Maintain detailed test reports for each equipment variant, noting logic types, temperature classes, and EMC zones
• Collaborate cross-functionally (engineering, quality assurance, procurement) to ensure all affected hardware and modules are addressed
• Update declarations of conformity and technical documentation to reflect the revised requirements

Conclusion / Next Steps

The December 2025 publication of EN IEC 61131-2:2025 marks a major milestone in manufacturing engineering standards. For businesses and professionals in industrial automation, adopting this standard is not only required for market compliance but is a pathway to superior product performance, less downtime, and increased customer satisfaction.

Key takeaways:

• EN IEC 61131-2:2025 is now the foundational reference for PLC and PAC equipment requirements and tests
• Significant technical updates have modernized requirements, testing, and documentation
• Early adoption will accelerate time-to-market and bolster competitive standing

Recommendations:

1. Audit your current products and designs to identify gaps vs. the new requirements
2. Update procurement and technical specifications to reference EN IEC 61131-2:2025
3. Train engineering and quality teams on the revised standard
4. Explore the full details and latest guidance via iTeh Standards

Stay ahead in manufacturing engineering—review the new standard in full: View EN IEC 61131-2:2025 on iTeh Standards

By leveraging this latest international specification, organizations can build more resilient, future-proof automated processes and ensure full compliance with evolving global benchmarks. For ongoing updates and expert guidance on standards in manufacturing engineering, continue to follow iTeh Standards.