This is the procedure to create a sub-circuit from a part of an existing network like the one shown below:
First, add the port connectors.
Click the Options tab, then click New Port Connector in the Subcircuit section of the toolbar.
This opens the New Port Connector window
Select Power (for a power signal) and enter a port name in the Port Name: field, then click Place.
Connect the newly-created port to the appropriate segment and repeat the operation for each signal that will display outside of the subcircuit.
Click and drag to select the parts of the model to encapsulate in a subcircuit.
With the parts highlighted, click Create Subcircuit Block... in the Options toolbar.
This opens the Subcircuit Wizard.
Select The selected items in the current circuit and click Next.
Specify the desired pin positions and click Next.
Unless you want to reposition pins on the subcircuit block, simply enter a name for the subcircuit in the Symbol Name field and click Next.
Click the checkbox to save the subcircuit in a library check the box and provide the library name where to save it and click Finish.
Delete the blocks used to create the sub-circuit if needed and connect the sub-circuit to the desired location.
Right-click the subcircuit and select Subcircuit info to view subcircuit content. The subcircuit Properties window appears.
Click Open.
The subcircuit window appears and you can view all its components.
Finally, start the model to verify that it is functioning properly.
