Defining and Handling Initial Conditions

You can define the initial values of model parameters to be used during the experiment.

Note that defining or modifying these execution model values do not modify the model values.

This task shows you how to:

See Also
About Behavior Experience
About Excitations

Define an Initial Condition

You can define the initial values of model parameters to be used during the experiment.

Before you begin: The Excitaion values box must be editable, indicated by .
  1. Select a scenario in the tree.
  2. From the Scenario section of the action bar, click Edit Probes and Excitations .
    The Scenario window appears and displays the model structure from the functional or logical component of the dynamic behavior.
  3. Expand the behavior and double-click the Excitation values box to edit it.
  4. Enter, modify or remove a value in the Excitation Values box.

    Note: You can enter a value in a compatible unit, it is converted to the current unit; for example, if you enter 10cm it is converted to 100mm if mm is the current unit. If you enter a value without unit, the current unit is assumed. See also Scenario Window.

    In the tree, a Initial Condition node with the new initial value appears in the following locations:

    Notes:
    • The initial value is a knowledge parameter.
    • If the signal has a known magnitude/unit from Modelica.SIUnit or is of a basic type (Real, Integer, Boolean, or String), the initial value gets the corresponding Knowledge type. If not, it is a String (case for enumeration, or unknown type).
    • To display values for parameters in the tree, you must activate the Display values in the specification tree preference from Me > Preferences > App Preferences > 3D Modeling > Multi Discipline Automated Engineering > Basics, the Parameters & Relations tab, the Parameters tree view group.
  5. To delete an initial condition, remove the corresponding text in the Scenario window.

    Important: If you change or delete a shared excitation, it is also changed or deleted in all other scenarios where it is used. To create an excitations that is not shared, you have to copy it. For more information about copying excitations, see Copying and Pasting Excitations and Probes between Scenarios.

Change the Value of an Initial Condition

You can change the value of an existing initial condition.

You can change the value of an exiting initial condition in two ways:
  • Double-click the value in the Scenario window and edit it.
  • Right-click the icon for the initial condition in the tree and select [signalname].object > Definition. An Edit Parameter dialog box appears. Here you can edit the initial value. Click OK to confirm the change.
    Tip: You can also double-click the icon. You might have to double-click twice, once to select the category, once to select the initial value icon.
    Important: The initial condition must be unlocked for this alternative to work. See next section.
    Note: For a shared initial conditon, you can work with the icon in the Scenario category or the icon in the Excitations category, they are the same.
    Important: If you change or delete a shared excitation, it is also changed or deleted in all other scenarios where it is used. To create an excitations that is not shared, you have to copy it. For more information about copying excitations, see Copying and Pasting Excitations and Probes between Scenarios.

Lock or Unlock an Initial Condition Knowledge Parameter Value

You can lock or unlock an initial condition. This means that the knowledge value of the initial condition cannot be modified from other apps.

Important: Note the difference between:
  • The hanglock in the Scenario window - this hanglock controls if the variable can be edited (applying an initial condition or forcing the value).
  • The hanglock on the initial condition icon in the tree - a hanglock here means that the knowledge value of the initial condition is locked.

  1. To lock an initial condition, right-click the icon for the initial value in the tree and select [signalname].object > Lock.
  2. To unlock the initial condition again, right-click the icon for the initial value in the tree and select [signalname].object > Unlock.

Note: For a shared initial conditon, you can work with the icon in the Scenario category or the icon in the Excitations category, they are the same.
Important: If you change or delete a shared excitation, it is also changed or deleted in all other scenarios where it is used. To create an excitations that is not shared, you have to copy it. For more information about copying excitations, see Copying and Pasting Excitations and Probes between Scenarios.

Edit the Formula of the Knowledge Parameter of an Initial Condition

You can edit the formula for the knowledge parameter of an initial value.

To edit the formula for the knowledge parameter of an initial value, right-click the icon for the initial value in the tree, and select [signalname].object > Edit Formula. .
The Formula Editor appears to let you edit the formula. For information about formulas, see the Knowledge Basics: Managing Relations: Formulas: Creating a Formula.
Tips:
  • You can click an item in the tree and, from the Tools section of the action bar, click Formula to display knowledge parameters and related formulas for that item.
  • There might be more knowledge commands available in the context menu of the signal operator result icon. For information about them, see the Knowledge Basics.
Note: For a shared initial conditon, you can work with the icon in the Scenario category or the icon in the Excitations category, they are the same.
Important: If you change or delete a shared excitation, it is also changed or deleted in all other scenarios where it is used. To create an excitations that is not shared, you have to copy it. For more information about copying excitations, see Copying and Pasting Excitations and Probes between Scenarios.