Introducing SFCs

SFCis another IEC 61131-3 language that allows you to program visually using a flowchart construct. The IEC SFC language is based on the GRAFCET language, which was the original industrial automation flowchart programming language. In some regions and within some companies, you will find that the terms SFC and GRAFCET are used interchangeably. Like other IEC-based languages, it can share commonIEC elements and reference tags, as well as objects created in other languages, with your Logix program. SFC is a powerful, high-level language, similar to Function Block Diagram. Often, you can create the equivalent functionality of 40 Ladder Logic rungs in a few SFC steps. An SFC routine (again like Function Block) will typically have more computational overhead than the same routine developed using low-level languages such as ladder logic or structured text. SFC routines are very easy to debug and maintain because of their compact visual design. SFC has its strengths...