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Timing Diagram

One of four types of Interaction diagram. (The other three are Sequence Diagrams, Interaction Overview Diagrams and Communication Diagrams.)

A Timing diagram defines the behavior of different objects within a time-scale. It provides a visual representation of objects changing state and interacting over time.

You can use Timing diagrams to define hardware-driven or embedded software components; for example, those used in a fuel injection system or a microwave controller. You can also use Timing diagrams to specify time-driven business processes.

To create and edit a Timing diagram, see the following topics:

Example Diagram

An example of a Timing diagram is shown below:

Example of a Timing Diagram

(See OMG UML Superstructure Specification, v2.1.1, p. 454, figures 14.30 and 14.31).

Toolbox Elements and Message

Select Timing diagram elements and connectors from the Timing pages of the Toolbox.


Click on the following elements and connectors for more information.

Timing Diagram Elements

Timing Diagram Message











OMG UML Specification

The OMG UML specification (UML Superstructure Specification, v2.1.1, p. 517) states:

Timing Diagrams are used to show interactions when a primary purpose of the diagram is to reason about time. Timing diagrams focus on conditions changing within and among Lifelines along a linear time axis.

Timing diagrams describe behavior of both individual classifiers and interactions of classifiers, focusing attention on time of occurrence of events causing changes in the modeled conditions of the Lifelines.

The OMG UML specification (UML Superstructure Specification, v2.1.1, p. 519) also states:

The primary purpose of the timing diagram is to show the change in state or condition of a lifeline (representing a Classifier Instance or Classifier Role) over linear time. The most common usage is to show the change in state of an object over time in response to accepted events or stimuli. The received events are annotated as shown when it is desirable to show the event causing the change in condition or state.