View Sample Time Information

View Sample Time Display

Simulink® models can display color coding and annotations that represent specific sample times. As shown in the table Designations of Sample Time Information, each sample time type has one or more colors associated with it. You can display the blocks and signal lines in color, the annotations in black, or both the colors and the annotations. To choose one of these options:

  1. In the Simulink model window, select Display > Sample Time.

  2. Select Colors, Annotations, or All.

Selecting All results in the display of both the colors and the annotations. Regardless of your choice, Simulink performs an Update Diagram automatically. To turn off the colors and annotations:

  1. Select Display > Sample Time.

  2. Select Off.

Simulink performs another Update Diagram automatically.

Your Sample Time Display choices directly control the information that the Sample Time Legend displays.


The discrete sample times in the table Designations of Sample Time Information represent a special case. Five colors indicate the fastest through the fifth fastest discrete rate. A sixth color, orange, represents all rates that are slower than the fifth discrete rate. You can distinguish between these slower rates by looking at the annotations on their respective signal lines.

Sample Time Legend

You can view the Sample Time Legend for an individual model or for multiple models. Additionally, you can prevent the legend from automatically opening when you select options on the Sample Time menu.

Viewing the Legend

To assist you with interpreting your block diagram, a sample time legend contains the sample time color, annotation, description, and value for each sample time in the model. You can use one of three methods to view the legend, but first update the diagram.

  1. In the Simulink model window, select Simulation > Update Diagram.

  2. Select Display > Sample Time > Sample Time Legend or press Ctrl + J.

In addition, when you select Colors, Annotations, or All from the Sample Time menu, Simulink updates the model diagram and opens the legend by default. The legend contents reflect your Sample Time Display choices. By default or if you have selected Off, the legend contains a description of the sample time and the sample time value. If you turn colors on, the legend displays the appropriate color beside each description. Similarly, if you turn annotations on, the annotations appear in the legend.

The legend does not provide a discrete rate for all types of sample times. For asynchronous and variable sample times, the legend displays a link to the block that controls the sample time in place of the sample time value. Clicking one of these links highlights the corresponding block in the block diagram. The checkbox to show discrete value as 1/period is enabled in presence of the discrete rate.

The rate listed under hybrid and asynchronous hybrid models is Not Applicable because these blocks do not have a single representative sample time.

When checked, the discrete period is displayed as 1/period, for a non zero offset displays as offset/period. For variable sample times, the legend uses >> to indicate that the controller block of the sample time is in a model reference hierarchy. Click >> to drill down to that block


The Sample Time Legend displays all of the sample times in the model, including those that are not associated with any block. For example, if the fixed step size is 0.1 and all of the blocks have a sample time of 0.2, then both rates (i.e., 0.1 and 0.2) appear in the legend.

For subsequent viewings of the legend, update the diagram to access the latest known information.

Turning the Legend Off

If you do not want to view the legend upon selecting Sample Time Display:

  1. In the Simulink Editor, select File > Simulink Preferences

  2. In the General pane, clear Open the sample time legend when the sample time display is changed and click Apply.

Viewing Multiple Legends

If you have more than one model open and you view the Sample Time Legend for each one, a single legend window appears with multiple tabs. Each tab contains the name of the model and the respective legend information. The following figure shows the tabbed legends for the f14 and vdp models.

Inspect Sample Times Throughout a Model

The Model Data Editor (View > Model Data) shows information about model data (signals, parameters, and states) in a sortable, searchable table. The Sample Time column shows you the sample time specified for each signal in a model. After you update the block diagram, the column also shows you the specific sample that each signal uses (for example, for signals for which you specify inherited sample time, -1). You can also use the column to specify sample times.

For more information about the Model Data Editor, see Configure Data Properties by Using the Model Data Editor.

See Also

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