IEC 61131

IEC 61131
Title	IEC 61131
Status	International standard
Started	1993
Organization	International Electrotechnical Commission
Abbreviation	IEC
Domain	Industrial automation, programmable logic controllers

IEC 61131

IEC 61131 is an international standard for programmable logic controllers published by the International Electrotechnical Commission. It defines architecture, programming languages, data types, and functional organization used in industrial automation across suppliers such as Siemens, ABB, Schneider Electric, Rockwell, and Mitsubishi Electric. The standard has influenced industrial consortia including PLCopen, OPC Foundation, ISA, NAMUR, and VDE.

Overview

The standard provides a framework for designing, programming, and integrating programmable logic controllers in domains served by Siemens, ABB, Schneider Electric, Rockwell, Mitsubishi Electric, Bosch, and Yokogawa. It addresses controller models akin to architectures used by Microsoft in embedded systems, by companies like Intel and ARM for real-time processors, and by vendors collaborating with PLCopen and OPC. The standard’s model meshes with industrial communication stacks standardized by IEC 61850, IEC 62351, PROFINET, and EtherNet/IP. Industry stakeholders such as Siemens, ABB, Schneider Electric, Rockwell, Mitsubishi Electric, Emerson, Honeywell integrate IEC 61131 guidance into products used in sectors including BASF, Dow, ExxonMobil, BP, and Shell.

Historical Development and Editions

The development coordinated by the International Electrotechnical Commission followed contributions from national committees like VDE, UL, CSA, and BSI. Early iterations paralleled work by groups such as PLCopen and research from institutions like ETH Zurich, Technical University of Munich, RWTH Aachen University, and Delft University of Technology. Major editions were issued alongside wider industrial standardization efforts exemplified by IEC 61508 and ISO 9001. Adoption accelerated as corporations such as Siemens, ABB, Schneider Electric, Rockwell, Mitsubishi Electric, Emerson, and Honeywell aligned product lines to successive releases. Regulatory and safety frameworks from European Commission, US Department of Energy, FDA, and agencies like OSHA influenced certification and mandatory compliance in sectors involving Shell, BP, TotalEnergies, and ExxonMobil.

Parts and Structure of the Standard

IEC 61131 is modular, comprising parts akin to families of documents produced by ISO, IEEE, IETF, and consortiums like PLCopen. The structure defines system requirements, programming languages, execution models, communication interfaces, and testing practices. Stakeholders such as Siemens, ABB, Schneider Electric, Rockwell, Mitsubishi Electric, GE, and Emerson map product capabilities to the parts when interfacing with industrial protocols like PROFIBUS, PROFINET, Modbus, DeviceNet, and EtherNet/IP. Research centers including Fraunhofer Society, SINTEF, CERN, and NIST have analyzed the parts to recommend interoperability strategies for process plants run by BASF, Dow, Bayer, and utilities operated by EDF, Enel, and E.ON.

Programming Languages and Model (PLCopen)

IEC 61131 specifies several programming languages: graphical languages similar to standards applied by Siemens in Step 7 and by Rockwell in RSLogix, textual languages comparable to approaches from Microsoft and Eclipse, and function block models championed by PLCopen. Languages include ladder diagrams used in products from Siemens, Rockwell, and Schneider Electric, function block diagrams used by ABB and Mitsubishi Electric, structured text related to compilers from GNU Compiler Collection and toolchains associated with Eclipse, instruction list historically influenced by microcontroller instruction sets from Intel and Motorola, and sequential function charts akin to control flow paradigms studied at ETH Zurich and TU Delft. PLCopen provides application programming interface profiles and XML exchange formats adopted by vendors such as Siemens, ABB, Schneider Electric, Rockwell, and Mitsubishi Electric for tool interoperability with vendor products and engineering suites like Siemens TIA Portal, Rockwell Studio 5000, and Schneider EcoStruxure.

Conformance, Certification, and Testing

Conformance regimes are implemented by certification bodies such as UL, TÜV SÜD, TÜV Rheinland, DEKRA, and national agencies like BSI and VDE. Test suites and interoperability labs run by PLCopen, OPC Foundation, PI, and FieldComm Group check implementations from Siemens, ABB, Schneider Electric, Rockwell, and Mitsubishi Electric. Academic validation has been conducted at RWTH Aachen University, Technical University of Munich, and Manchester. Certification is often tied to safety standards such as IEC 61508 and industry schemes enforced by ISO, API, and energy regulators like FERC.

Applications and Industry Adoption

IEC 61131-based controllers are used in manufacturing plants run by Toyota, Volkswagen, Ford, GM, in process facilities operated by BASF, Dow, ExxonMobil, and in utilities managed by EDF, Enel, National Grid, and Siemens Energy. Automation integrators such as ABB, Schneider Electric, Rockwell, Siemens, and Mitsubishi Electric implement the standard in sectors including Airbus, Boeing, ArcelorMittal, Rio Tinto, and Cargill. Systems employing IEC 61131 interact with SCADA platforms from Wonderware, GE Digital, and Aveva and with MES solutions from Siemens, SAP, and Oracle.

Security, Safety, and Future Directions

Security and safety considerations link IEC 61131 implementations with standards and initiatives from IEC 62443, ISO/IEC 27001, NIST, and ENISA. Vendors including Siemens, ABB, Schneider Electric, and Rockwell implement secure firmware practices comparable to supply-chain recommendations by ISO, NIST, and European Commission programs. Functional safety integration is coordinated with IEC 61508 and ISO 13849 for lifeline industries served by Shell, BP, ExxonMobil, TotalEnergies, and Royal Dutch Shell. Future directions include tighter model integration promoted by PLCopen, cloud-connected automation aligning with initiatives from Microsoft, AWS, Google Cloud, and edge paradigms driven by Intel and ARM, while research labs at Fraunhofer Society, SINTEF, ETH Zurich, and TU Delft explore formal verification, model checking, and cyber-resilience techniques used in projects with Siemens, ABB, and Schneider Electric.

Category:Industrial automation standards