SysML - Modeling a sequence diagram

Use case diagrams are normally detailed by related behavioral diagrams, such as sequence diagrams which enable control flows to be expressed.

Here we want to illustrate the sequence of operations/events related to the “Operate the Plant” use case scenario described in the previous figure. Sequence diagrams can also be related to block diagrams, since they express interaction between the different elements present in the system. In the figure on the right, we see several actions, such as the starting/stopping of the experimental plant unit in question, and actions based on some control strategies, among others.