About Blocks :: Working with Blocks (Using Simulink)

Using Simulink

About Blocks

Blocks are the elements from which Simulink models are built. You can model virtually any dynamic system by creating and interconnecting blocks in appropriate ways. This section discusses how to use blocks to build models of dynamic systems.

Block Data Tips

On Microsoft Windows, Simulink displays information about a block in a pop-up window when you allow the pointer to hover over the block in the diagram view. To disable this feature or control what information a data tip includes, select Block data tips options from the Simulink View menu.

Virtual Blocks

When creating models, you need to be aware that Simulink blocks fall into two basic categories: nonvirtual 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 following table lists Simulink virtual and conditionally virtual blocks.

Block Name
Condition Under Which Block Is Virtual

Bus Selector
Always virtual.

Demux
Always virtual.

Enable
Virtual unless connected directly to an Outport block.

From
Always virtual.

Goto
Always virtual.

Goto Tag Visibility
Always virtual.

Ground
Always virtual.

Inport
Virtual unless the block resides in a conditionally executed or atomic subsystem and has a direct connection to an outport block.

Mux
Always virtual.

Outport
Virtual when the block resides within any subsystem block (conditional or not), and does not reside in the root (top-level) Simulink window.

Selector
Virtual except in matrix mode.

Signal Specification
Always virtual.

Subsystem
Virtual unless the block is conditionally executed and/or the block's Treat as Atomic Unit option is selected.

Terminator
Always virtual.

Trigger
Virtual when the outport port is not present.

Block Name	Condition Under Which Block Is Virtual
Bus Selector	Always virtual.
Demux	Always virtual.
Enable	Virtual unless connected directly to an Outport block.
From	Always virtual.
Goto	Always virtual.
Goto Tag Visibility	Always virtual.
Ground	Always virtual.
Inport	Virtual unless the block resides in a conditionally executed or atomic subsystem and has a direct connection to an outport block.
Mux	Always virtual.
Outport	Virtual when the block resides within any subsystem block (conditional or not), and does not reside in the root (top-level) Simulink window.
Selector	Virtual except in matrix mode.
Signal Specification	Always virtual.
Subsystem	Virtual unless the block is conditionally executed and/or the block's Treat as Atomic Unit option is selected.
Terminator	Always virtual.
Trigger	Virtual when the outport port is not present.

Working with Blocks Editing Blocks