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To open the SISO Tool Preferences editor, select SISO Tool Preferences from the Edit menu of the Graphical Tuning window. This window opens.
The Units pane has settings for the following units:
The default units are rad/second.
Magnitude — Decibels (dB) or absolute value (abs)
Phase — Degrees or radians
For frequency and magnitude axes, you can select logarithmic or linear scales.
In the Time Delays pane, specify the order for Padé approximations of delays in your system as either:
Actual Padé order
Bandwidth of accuracy (rad/s) — The highest frequency at which the approximated response matches the actual system. The software computes and displays the corresponding Padé order.
The following compensator design tools do not support systems with exact time delays. If your system has exact continuous-time delays, these tools automatically compute a Padé approximation of the delays. In this case, you receive a notification.
PID automated tuning
IMC automated tuning
LQG automated tuning
Loop shaping automated tuning
Use the Style pane to toggle grid visibility and set font preferences and axes foreground colors for all plots in the Graphical Tuning Window. This figure shows the Style pane.
Select the box to activate grids for all plots in the GRAPHICAL Tuning Window
Set the font size, weight (bold), and angle (italic) by using the menus and check boxes.
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.
You can use this window to choose axes foreground colors without having to set RGB (red-green-blue) values numerically. To make your selections, click on the colored rectangles and press OK. If you want a broader range of colors, click the More Colors button. This opens the More Colors window, as shown in the following figure.
Click on the array of color swatches to select a color. Alternatively, click the HSB tab to use the Hue Saturation Brightness (HSB) color picker. Or, click the RGB tab to enter numeric RGB values.
When you select a color, the Preview section of the window changes to preview your selection. Click OK to accept the choice. Click Reset to reset the selection.
The Options pane, shown below, has selections for compensator format and Bode diagrams.
You can make the following selections:
Compensator Format — Select the time constant, natural frequency, or zero/pole/gain format. The time constant format is a factorization of the compensator transfer function of the form
where DC is compensator DC gain, Tz1, Tz2, ..., are the zero time constants, and Tp1, Tp2, ..., are the pole time constants.
The natural frequency format is
where DC is compensator DC gain, ωz1, and ωz2, ... and ωp1, ωp2, ..., are the natural frequencies of the zeros and poles, respectively.
The zero/pole/gain format is
where K is the overall compensator gain, and z1, z2, ... and p1, p2, ..., are the zero and pole locations, respectively.
Bode Options — By default, the GRAPHICAL Tuning Window shows the plant and sensor poles and zeros as blue x's and o's, respectively. Clear this check box to eliminate the plant's poles and zeros from the Bode plot. Note that the compensator poles and zeros (in red) will still appear.
The Line Colors pane, shown below, has selections for specify the colors of the lines in the response plots of the Graphical Tuning Window.
To change the colors of plot lines associated with parts of your model, specify 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 the RGB values numerically, click the Select button to open the Select Color window. See Select colors for more information.