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Sequence Viewer

Display messages, events, states, transitions, and functions between blocks during simulation

  • Library:
  • Simulink / Messages & Events

    Simulink Test



  • Sequence Viewer block


The Sequence Viewer block displays messages, events, states, transitions, and functions between certain blocks during simulation. The blocks that you can display are called lifeline blocks and include:

  • Subsystems

  • Referenced models

  • Blocks that contain messages, such as Stateflow® charts

  • Blocks that call functions or generate events, such as Function Caller, Function-Call Generator, and MATLAB Function blocks

  • Blocks that contain functions, such as Function-Call Subsystem and Simulink Function blocks

To see states, transitions, and events for lifeline blocks in a referenced model, you must have a Sequence Viewer block in the referenced model. Without a Sequence Viewer block in the referenced model, you can see only messages and functions for lifeline blocks in the referenced model.


The Sequence Viewer block does not display function calls generated by MATLAB Function blocks and S-functions.


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Number of digits for time increment precision. When using a variable step solver, change this parameter to adjust the time precision for the sequence viewer. By default the block supports 3 digits of precision.

Suppose the block displays two events that occur at times 0.1215 and 0.1219. Displaying these two events precisely requires 4 digits of precision. If the precision is 3, then the block displays two events at time 0.121.

Programmatic Use

Block Parameter: VariableStepTimePrecision
Type: character vector
Values: '3' | scalar
Default: '3'

Total number of events before the last event to display.

For example, if History is 5 and there are 10 events in your simulation, then the block displays 6 events, including the last event and the five events prior the last event. Earlier events are not displayed. The time ruler is greyed to indicate the time between the beginning of the simulation and the time of the first displayed event.

Each send, receive, drop, or function call event is counted as one event, even if they occur at the same simulation time.

Programmatic Use

Block Parameter: History
Type: character vector
Values: '1000' | scalar
Default: '1000'

Block Characteristics

Data Types

Boolean | bus | double | enumerated | fixed point | integer | single

Direct Feedthrough


Multidimensional Signals


Variable-Size Signals


Zero-Crossing Detection


Extended Capabilities

Introduced in R2015b