Note: The animations could only work if the "Zoom" of the browser is equal to 100%. If you need to adjust, go to settings of the browser.
Alternative sequences are used when the GRAFCET could evolve through one (or more) available sequence(s). This sequence starts with a OR divergence.
Situations in which the GRAFCET evolves by one or more alternative paths, starting from a certain step. It is represented by a horizontal line with a one preceding link and two or more succeeding links.
Its representation consists in a horizontal line receiving preceding links with just one succeeding link. In order that one transition is cleared at least one the preceding steps must be active.
Simultaneous sequences are used when several sequences are required to be activated in parallel, from a given step. These sequences start with an AND divergence.
Its representation is throught a horizontal straight double receiving the input links and with one single output link. In order as the AND convergence may evolve it is required that all the preceding steps of the double line (synchronization) are active and their output transition-condition is true.