progr. |
in SFC methodology, every step can be associated with one or more actions. An action contains a description of some behaviour that should occur as a result of the step being activated. An action is depicted as a rectangular box that is attached to a step. The description of an action can be given using any of the IEC languages, i.e. ST, FBD, LD or IL (см. Robert W. Lewis: Programming industrial control systems using IEC 1131-3) |