Definition
A step represents a situation where the behaviour of a POU with respect to its inputs and outputs follows a set of rules defined by the associated actions of the step. A step is either active or inactive. At any given moment, the state of the POU is defined by the set of active steps and the values of its internal and output variables.A step is represented graphically by a block containing a step name in the form of an identifier. The directed link(s) into the step can be represented graphically by a vertical line attached to the top of the step. The directed link(s) out of the step can be represented by a vertical line attached to the bottom of the step.
GF_ProjectVX does not set any constraint on the maximum number of steps per SFC.Step FlagThe step flag (active or inactive state of a step) can be represented by the logic value of a Boolean variable ***_x, where *** is the step name. This Boolean variable has the value TRUE when the corresponding step is active and FALSE when it is inactive. The scope of step names and step flags is local to the program organization unit where the steps appear.
Users cannot assign a value directly to a step state.
| Representation | Description |
 | Step(graphical representation with direct links) |
| Representation | Description |
| Step Name_x | Step flag= TRUE when Step Name_x is active= FALSE otherwise |