AiVibeIEC 61131-3
IEC 61131-3 is the international standard that defines programming languages, data types and software structure for programmable controllers, giving PLC programmers a common set of languages and concepts across vendors.
IEC 61131-3 is Part 3 of the IEC 61131 series on programmable controllers. It defines two graphical languages, ladder diagram (LD) and function block diagram (FBD); two textual languages, structured text (ST) and instruction list (IL), the latter deprecated in the 2013 third edition; and sequential function chart (SFC) for organising sequential behaviour. It also specifies elementary and derived data types, variables and program organisation units, namely functions, function blocks and programs, arranged within configurations, resources and tasks.
Most PLC and soft-PLC engineering environments implement IEC 61131-3, although support for each language and for features such as the object-oriented extensions varies by vendor. A common standard makes training transferable, lets teams mix languages within one project and eases migration, although programs rarely move between vendors without conversion work.
Compliance claims should be checked against each vendor's compliance statement, since the standard leaves some features implementation-dependent. PLCopen, a vendor-independent association, publishes guidance, certification and an XML exchange format built on IEC 61131-3. The related IEC 61499 standard extends the function block concept to event-driven, distributed applications.
Key points
- Part 3 of the IEC 61131 series on programmable controllers
- Graphical languages: ladder diagram and function block diagram
- Textual languages: structured text and the deprecated instruction list
- Sequential function chart structures programs into steps and transitions
- Defines data types, functions, function blocks, programs and tasks
Where AiVibe comes in
AiVibe designs and manufactures the AiAmbA AI Factory, whose edge devices and AI agents let people talk to PLC, CNC and robot controllers in plain language. Agents only propose changes, a trained operator confirms each one, and the AI Factory never replaces a machine's control or safety systems.
Related terms
- Programmable Logic Controller (PLC)PLC & Industrial Control
- Ladder Logic (Ladder Diagram, LD)PLC & Industrial Control
- Function Block Diagram (FBD)PLC & Industrial Control
- Structured Text (ST)PLC & Industrial Control
- Sequential Function Chart (SFC)PLC & Industrial Control
- IEC 61499PLC & Industrial Control