A Practical Guide to SysML, 2nd Edition

11.5 State Machines and Operation Calls

State machines can respond to operation calls on their parent block via call events. A call event may either be handled in a synchronous fashion—that is, the caller is blocked while waiting for a response—or asynchronously, which results in similar behavior to the receipt of a signal. The state machine executes all actions triggered by the call event until it has reached another state, and then returns any outputs created by the actions to the caller.

One of the components used by the surveillance system’s operators is a video player that allows them to review recorded surveillance data. The Video Player block, shown in Figure 11.8, provides a set of operations in its interface to control playback. Although ...