Customizing Response Plots Using the Response Plots Property Editor

Opening the Property Editor

After you create a response plot, there are two ways to open the Property Editor:

  • Double-click in the plot region

  • Select Properties from the right-click menu

Before looking at the Property Editor, open a step response plot using these commands.

load ltiexamples
step(sys_dc)

This creates a step plot. Select Properties from the right-click menu. Note that when you open the Property Editor, a set of black squares appear around the step response, as this figure shows:

SISO System Step Response

Overview of Response Plots Property Editor

This figure shows the Property Editor dialog box for a step response.

The Property Editor for Step Response

In general, you can change the following properties of response plots. Note that only the Labels and Limits panes are available when using the Property Editor with Simulink® Design Optimization™ software.

  • Titles and X- and Y-labels in the Labels pane.

  • Numerical ranges of the X and Y axes in the Limits pane.

  • Units where applicable (e.g., rad/s to Hertz) in the Units pane.

    If you cannot customize units, as is the case with step responses, the Property Editor will display that no units are available for the selected plot.

  • Styles in the Styles pane.

    You can show a grid, adjust font properties, such as font size, bold and italics, and change the axes foreground color

  • Change options where applicable in the Options pane.

    These include peak response, settling time, phase and gain margins, etc. Plot options change with each plot response type. The Property Editor displays only the options that make sense for the selected response plot. For example, phase and gain margins are not available for step responses.

As you make changes in the Property Editor, they display immediately in the response plot. Conversely, if you make changes in a plot using right-click menus, the Property Editor for that plot automatically updates. The Property Editor and its associated plot are dynamically linked.

Labels Pane

To specify new text for plot titles and axis labels, type the new string in the field next to the label you want to change. Note that the label changes immediately as you type, so you can see how the new text looks as you are typing.

Limits Pane

Default values for the axes limits make sure that the maximum and minimum x and y values are displayed. If you want to override the default settings, change the values in the Limits fields. The Auto-Scale box automatically clears if you click a different field. The new limits appear immediately in the response plot.

To reestablish the default values, select the Auto-Scale box again.

Units Pane

You can use the Units pane to change units in your response plot. The contents of this pane depend on the response plot associated with the editor.

The following table lists the options available for the response objects. Use the menus to toggle between units.

Optional Unit Conversions for Response Plots

Response Plot

Unit Conversions

Bode and
Bode Magnitude

  • Frequency

    By default, shows rad/TimeUnit where TimeUnit is the system time units specified in the TimeUnit property of the input system.

     Frequency Units Options

  • Frequency scale is logarithmic or linear.

  • Magnitude in decibels (dB) or the absolute value

  • Phase in degrees or radians

Impulse

  • Time.

    By default, shows the system time units specified in the TimeUnit property of the input system.

     Time Units Options

Nichols Chart

  • Frequency

    By default, shows rad/TimeUnit where TimeUnit is the system time units specified in the TimeUnit property of the input system.

     Frequency Units Options

  • Phase in degrees or radians

Nyquist Diagram

  • Frequency

    By default, shows rad/TimeUnit where TimeUnit is the system time units specified in the TimeUnit property of the input system.

     Frequency Units Options

Pole/Zero Map

  • Time.

    By default, shows the system time units specified in the TimeUnit property of the input system.

     Time Units Options

  • Frequency

    By default, shows rad/TimeUnit where TimeUnit is the system time units specified in the TimeUnit property of the input system.

     Frequency Units Options

Singular Values

  • Frequency

    By default, shows rad/TimeUnit where TimeUnit is the system time units specified in the TimeUnit property of the input system.

     Frequency Units Options

  • Frequency scale is logarithmic or linear.

  • Magnitude in decibels or the absolute value using logarithmic or linear scale

Step

  • Time.

    By default, shows the system time units specified in the TimeUnit property of the input system.

     Time Units Options

Style Pane

Use the Style pane to toggle grid visibility and set font preferences and axes foreground colors for response plots.

You have the following choices:

  • Grid — Activate grids by default in new plots.

  • Fonts — Set the font size, weight (bold), and angle (italic) for fonts used in response plot titles, X/Y-labels, tick labels, and I/O-names.

  • Colors — Specify the color vector to use for the axes foreground, which includes the X-Y axes, grid lines, and tick labels. Use a three-element vector to represent red, green, and blue (RGB) values. Vector element values can range from 0 to 1.

    If you do not want to specify RGB values numerically, click the Select button to open the Select Color dialog box. See Select colors for more information.

Options Pane

The Options pane allows you to customize response characteristics for plots. Each response plot has its own set of characteristics and optional settings; the table below lists them. Use the check boxes to activate the feature and the fields to specify rise or settling time percentages. When you change the value in a field, press the Enter key on your keyboard to update the response plot.

Response Characteristic Options for Response Plots

Plot

Customizable Feature

Bode Diagram and Bode Magnitude

Select lower magnitude limit
Adjust phase offsets to keep phase close to a particular value, within a range of ±180º, at a given frequency.
Unwrap phase (default is unwrapped)

Impulse

Show settling time within xx% (specify the percentage)

Nichols Chart

Select lower magnitude limit
Adjust phase offsets to keep phase close to a particular value, within a range of ±180º, at a given frequency.
Unwrap phase (default is unwrapped)

Nyquist Diagram

None

Pole/Zero Map

None

Sigma

None

Step

Show settling time within xx% (specify the percentage)
Show rise time from xx to yy% (specify the percentages)

Editing Subplots Using the Property Editor

If you create more than one plot in a single figure window, you can edit each plot individually. For example, the following code creates a figure with two plots, a step and an impulse response with two randomly selected systems:

subplot(2,1,1)
step(rss(2,1))
subplot(2,1,2)
impulse(rss(1,1))

After the figure window appears, double-click in the upper (step response) plot to activate the Property Editor. You will see a set of small black squares appear around the step response, indicating that it is the active plot for the editor. To switch to the lower (impulse response) plot, just click once in the impulse response plot region. The set of black squares switches to the impulse response, and the Property Editor updates as well.

Was this topic helpful?