When creating models, you need to be aware that Simulink® blocks fall into two basic categories: nonvirtual blocks and virtual blocks. Nonvirtual blocks play an active role in the simulation of a system. If you add or remove a nonvirtual block, you change the model's behavior. Virtual blocks, by contrast, play no active role in the simulation; they help organize a model graphically. Some Simulink blocks are virtual in some circumstances and nonvirtual in others. Such blocks are called conditionally virtual blocks. The table lists Simulink virtual and conditionally virtual blocks.
| Block Name | Condition Under Which Block Is Virtual |
|---|---|
Virtual if input bus is virtual. | |
Virtual if output bus is virtual. | |
Virtual if input bus is virtual. | |
Always virtual. | |
Virtual unless connected directly to an Outport block. | |
Always virtual. | |
Always virtual. | |
Always virtual. | |
Always virtual. | |
Virtual unless the block resides in a conditionally executed or atomic subsystem and has a direct connection to an Outport block. | |
Always virtual. | |
Virtual when the block resides within any subsystem block (conditional or not), and does not reside in the root (top-level) Simulink window. | |
Virtual only when Number of input dimensions specifies
| |
Always virtual. | |
Virtual unless the block is conditionally executed or the Treat as atomic unit check box is selected. You can check if a block is
virtual with the | |
Always virtual. | |
Virtual when the output port is not present. |