Creating and Connecting Subsystems

Subsystems are used in the creation of block diagrams to nest assembled items within other circuits or models.

Use the Model Browser to examine the relationship between the hierarchical parents and children of your schematic. Open folders downstream of the parent folder to see children, and upstream through the hierarchy of folders to see parents.

To create a subsystem:

• From the System library of the Library Browser, Drag a Subsystem block onto the work area
• Double-click within the Subsystem block, and a new canvas appears: you are now at the first child level.
• Continue to build your model or circuit as desired
• You can copy and paste components or connected components into subsystems and thus across parent/child layers.
• Then select the level of hierarchy desired to navigate between parents and children from the Model Browser.
  • Expose all levels and relationships in the hierarchy by clicking the triangle icon until it faces down.
  • Conceal all relationships in the hierarchy by clicking the triangle icons until they face right.
  
  

OR

• Use the Navigation Bar system above the diagram model to navigate from the subsystem back to the parent
  • The Model Browser can also be view from the Navigation Bar as well using this icon

To create a subsystem from selection

• Select elements on the canvas you want to move inside a subsystem
• Right click on the selection
• Select "Create Subsystem" from the context menu

Note: The hotkeys, or shortcut keys, for create subsystem from selection is CTRL+G.

Note: In the example above, we have two nested layers of schematics. MyModel is the parent of sub1.

About System > Power Ports:

• Power port blocks link signals from outside a system to the system.
• Power port blocks in a subsystem represent inputs to the subsystem. A signal arriving at a Power port on a Subsystem block originates from the associated connection in that subsystem. 
• A port's numbering on the Subsystem block at the parent level indicates the port where the signal arrives with the matching number at the child level.

To connect electrical signals across hierarchical levels:

Subsystems exchange signals between the inside and outside of the subsystem, or across their boundaries, by placing ports inside subsystems.  When adding a port block inside a subsystem, it is also visible on the subsystem block of the parent subsystem. Signals connected on both sides of the port share the same electrical node and same voltage, i.e., they are electrically connected. 

• Click twice to access the subsystem's contents. 
• Add one or more System > Electrical port(s) to connect the signal between the current (child) subsystem to the parent subsystem. 

• In the animated video above. we've connected one electrical ports to the left, and one to the right of the subsystem.
  

NOTE: The Subsystem block you previously created now has two terminals, or more specifically, ports, attached to it–-these are the connections you built internally at the child level to connect inside components. At the parent level, they are visible as ports of the subsystem.

• Connect the new subsystem that you have just built (at the parent level) to the rest of the circuit.

To add ports by connecting signals to the subsystem 

To move ports

Select the port and drag it across the subsystem border.

To rename a subsystem:

Select it and type the new name, clicking away from the block to save it. The new name is migrated to the Model Browser in the left tab.

To add an image to a subsystem:

To improve the layout of the circuit, and to help with organization and navigation, images can be added to subsystems, viewable from the parent. The option is available when selecting the subsystem and clicking on the import button in the sidebar.

You can remove the image by clicking the trash can beside Change image button from the Parameters sidebar.

To change the port location on the subsystem block

The location of the port on the subsystem block can be configured by changing their location and number parameters.  Ports can be located on the left, right, top, or bottom sides of the block.

When multiple ports are located on the same side of the block, the number parameters allow users to organize the ports in the desired order. 

• Navigate inside a subsystem
• Select the port you would like to relocate
• Go in the parameter sidebar
• Change the location or side of the port (top, left, right, bottom)
• Then, select the ordering of the port on that side of the block.
• Putting 1 indicates the first port on that side of the block; 2 means the second port on that side of the block, etc.