Describe System Behavior Using Sequence Diagrams
A sequence diagram represents the expected interaction between structural elements of an architecture as a sequence of message exchanges.
Use sequence diagrams to describe how the parts of a system interact.
Sequence diagrams are integrated with architecture models in System Composer™.
Author Sequence Diagram for Traffic Light Example: Interactively create and edit a sequence diagram and learn terminology.
Author Sequence Diagram Fragments: Learn how to implement fragments and more about fragment semantics.
Use Sequence Diagrams with Architecture Models: Create and use sequence diagrams with architecture models.
Synchronize Sequence Diagrams and Architecture Models: Learn how to synchronize sequence diagrams with architecture models.
A lifeline is represented by a head and a timeline that proceeds down a vertical dotted line.
The head of a lifeline represents a component in an architecture model.
A message sends information from one lifeline to another. Messages are specified with a message label.
A message label has a trigger and a constraint. A trigger determines whether the message occurs. A constraint determines whether the message is valid.
An annotation describes the elements of a sequence diagram.
Use annotations to provide detailed explanations of elements or workflows captured by sequence diagrams.
A fragment indicates how a group of messages within it execute or interact.
A fragment is used to model complex sequences, such as alternatives, in a sequence diagram.
An operand is a region in a fragment. Fragments have one or more operands depending on the kind of fragment. Operands can contain messages and additional fragments.
Each operand can include a constraint to specify whether the messages inside the operand execute. You can express the precondition of an operand as a MATLAB® Boolean expression using the input signal of any lifeline.