Introducing sequential function charts

Sequential Function Charts (SFC) is another IEC 61131-3 language, which allows you to visually program using a flow chart construct. The IEC SFC language is based on the GRAFCET language, which was the original industrial automation flow chart 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 IEC common elements and reference tags and objects created in other languages with your Logix program. SFC is a powerful high-level language similar to function block. 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...