Transition in SFC

Transitions are basic elements of SFC networks. A transition characterizes the condition when the controller passes from one step to another.

A transition is always associated with a Boolean transition condition. This condition can be realized by:

a single Boolean variable (TRUE/FALSE constants are also allowed).
a directly connected LD/FBD network with a Boolean result.
a coded transition written in the programming languages ST, FBD or LD. The coded transition is shown as separate node in the 'Transitions' subfolder of the SFC function block POU folder in the COMPONENTS area.