Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Automation fundamentals, platforms and components

SFC (sequential function chart)

Also known as: Sequential function chart, SFC

German: SFC (Ablaufsprache)

In IEC 61131-3, the sequential function chart (SFC) is a graphical language element for structuring programs as sequences of steps and transitions, with actions associated to steps. It supports alternative and simultaneous branches and derives from GRAFCET (IEC 60848).

  • Automation components
  • Standards

In one sentence

SFC is the IEC 61131-3 language for structuring control sequences as steps, transitions and actions, with alternative and parallel branches.

Example

The cleaning-in-place sequence is written in SFC: rinse, caustic wash, intermediate rinse, acid wash and final rinse, each step with its own actions.

How it applies

  • Engineering: SFC makes sequences visible: which step is active, which transition condition is missing. Actions within steps are written in other IEC 61131-3 languages. Simultaneous branches express Parallelism.
  • Operation and service: Many tools animate the active step online, which speeds up troubleshooting of a stuck Step chain.
  • Documentation: SFC charts can serve as the link between the functional specification and the code. Keep step numbers and names identical in the functional description, HMI messages and the program. Online changes to active sequences need special care and should be described in the service manual.

SFC vs. GRAFCET

GRAFCET (IEC 60848) is a specification language for describing the behavior of sequential control systems independently of implementation. SFC is its implementation-oriented counterpart for programming controllers under IEC 61131-3.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: IEC 61131-3:2013, Programmable controllers — Part 3: Programming languages

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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