Add a model connection

A model connection allows you to reference a single Model Type (typically a replaceable submodel) to reuse its equations, parameters, and variables in place of another Model Type. The referenced Model Type completely replaces the Model Type that connects to it. Therefore, the two Model Types can have different configurations or type declarations without affecting the connection. If you know that you'll be referencing a Model Type, the Model Type that connects to the referenced Model Type can even be a blank placeholder Model Type.

Because model connections reuse the equations in the referenced Model Type, you can use model connections to greatly reduce the number of equations that the software has to solve for the model instance. This reduction in the number of equations to solve improves the simulation performance.

For example, consider a Source Model Type that includes a State and a Reaction submodel. The Reaction submodel in turn includes its own State submodel.

Instead of including two separate State submodels in the Source Model Type, we can simplify the model by adding a model connection between the two State submodels. The Reaction submodel then reuses all the equations, variables, and parameters from the Source's State submodel instead of performing calculations in its own State submodel.

From a modeling standpoint, the Reaction submodel should use the same State configuration and values as the Source model. Therefore, the model connection provides us with the following modeling benefits:

• Reduces the number of equations to solve by the number of equations in the replaced State submodel, which improves the performance.

• Eliminates the possibility that the two State submodels solve to different, conflicting values due to rounding errors or configuration discrepancies.

Model connections can span the entire model hierarchy and can propagate through port connections.

Add a model connection

1. Ensure that the Model Writing role is selected. See Roles, Roles.

2. Open the Model Editor for the desired Model Type.

3. Expand the Connections section.

4. Select Add Connection .

   A new connection appears in the list of connections.

5. (Optional) Rename the new connection.

6. In the Type list, select Model.

7. In the From box, enter the name of the submodel that you want to reuse.

   You can use a submodel from any level in the model hierarchy. This submodel must appear in the submodels list in the Models section of either the model or one of its submodels.

8. In the To box, enter the name of the submodel that you want to replace with a reference to the Model Type specified in the To box.

   You can replace a submodel from any level in the model hierarchy. This submodel must appear in the submodels list in the Models section of either the model or one of its submodels.

   

9. (Recommended) Enter a Description for the connection.