5.1 Passing Parameters into Subcircuits Using the SIMPLIS_TEMPLATE Property

Exercise #1: Parameterize Using the Multi-Property Method

In this exercise, you will use the symbol editor to add a symbol property for each parameter. Although it is not strictly necessary, you will use the parameter name for the symbol property name. For example, the FC parameter will be saved on a symbol property named FC.

1. Open the schematic 5.4_parametrized_rc_filters_multi_prop.sxsch.
2. Select U2.
3. Right click to bring up the context menu, and then select Edit Symbol...to edit the symbol for the schematic component param_rc_multi_prop.sxcmp.
4. To add a symbol property for each name in the following table, follow the steps below:

   Symbol Property Name	Symbol Property Value
   FC	10k
   R_VAR	1k
   GAIN	1

   1. From the Symbol Editor menu, select Property/Pin > Add Property..., and then add a symbol property with the name and value from the table above.
   2. To display the symbol property between the name of the schematic component and the symbol, select Auto Normal = Top in Text Location group.
   3. Check the Show name and Selectable check boxes.
      Result: The configured dialog for the FC parameter is shown below:
      
   4. Click Ok to save the symbol property.
   5. Repeat steps a through d for the R_VAR and GAIN symbol properties.
      Result: The symbol with the added properties appears as follows:
      
5. To add the SIMPLIS_TEMPLATE property to pass the symbol properties FC, R_VAR, and GAIN through the symbol-to-subcircuit interface, follow these steps:
   1. From the Symbol Editor menu, select Property/Pin > Add Property....
   2. Type SIMPLIS_TEMPLATE in the Name field, and add the following in the Value field: <ref> <nodelist> <value> vars: FC=%FC% R_VAR=%R_VAR% GAIN=%GAIN%
   3. In the Text Location group, select Auto Normal = Top for the symbol property.
   4. Check the Hidden check box on the Add Property Dialog.
      Result: The configured SIMPLIS_TEMPLATE add property dialog should appear as follows:
      
   5. Click Ok to add the SIMPLIS_TEMPLATE property.
      Result: You have now configured the symbol to use the multi-property method. The symbol editor should appear as follows:
      
6. Press Ctrl+S to save the symbol.
7. Click Ok on the Save Symbol dialog to save the symbol to the component file, and then close the Symbol Editor window.
8. To update the instantiated symbols on the schematic, follow these steps:
   1. Select U1.
   2. Press and hold the Ctrl key while selecting U2.
      Result: Both symbols for U1 and U2 are selected:
      
   3. Right click to bring up the context menu and select Restore Properties...
      Result: A dialog opens, for you to confirm that you want to add the new properties to the instantiated symbols:
      
   4. Click Ok.
      Result: The schematic instances for U1 and U2 are updated with the new symbol properties:
      
9. Press F9 to run the simulation.
   Result: The design simulates in SIMPLIS and two gain curves are output, one for each of the two filters. The pole frequency is 10kHz for both filters as the passed parameters are identical for both U1 and U2.
   
10. Double-click on the FC property for U2, this will open the Edit Property dialog. Change the FC value to 30kHz. The Edit Property dialog should appear as follows:
11. Click Ok on the Edit Property dialog and run the simulation.
    Result: The blue output curve for the 30kHz filter now reflects the change to the FC parameter.
    

Discussion: Exercise #1

You can now double click on any of the symbol properties to edit the individual symbol properties. Since each symbol property is passed as a model parameter, you are directly editing the model parameters. This is one of the main advantages to the multi-property method. You can also choose which parameters to show and which to hide.