Initial steps and steps in FBD

Use an initial step and →steps in order to create a step sequence (an →SFC network).
Several steps are allowed per SFC network but only one initial step. See the notes under "SFC elements in drawing field" how to create/use SFC networks efficiently and correctly.

One or several →actions can be associated to each step (and each initial step as well). See "Evaluating the ST-code including the SFC networks" for information on when a step or initial step is active or inactive and the results of this.

Lines visualize the connections to the other FBD-elements in the drawing field.

Representation

Example for initial step with name S0:

Example for step with name S1:

images/download/thumbnails/414777755/InitialStep-version-1-modificationdate-1534228693463-api-v2.png

images/download/thumbnails/414777760/Step-version-1-modificationdate-1534228714946-api-v2.png

The step input in is located on the top edge, the step output out on the bottom edge, the step marker output X on the right edge.
The step input and the step output are connected to →transitions, the step marker output is usually connected to an action block.

Restrictions

  • Currently, the connections to these SFC elements are not possible within logi.CAD 3 because the appropriate SFC elements are not provided.

  • Although the usage of the step marker X, of the step time T and of the time of activation S is possible according to the →IEC-standard, they cannot be used within the FBD-editor.

  • It is only possible to resize initial steps and steps regarding their width. It is not possible to resize them regarding their height.