Subsystems

Group blocks into functional subsystems, create model hierarchy

As a model increases in size and complexity, you can simplify it by grouping blocks into subsystems. A subsystem is a set of blocks that you group into a single Subsystem block.

Using subsystems:

Establishes a hierarchical block diagram, where a Subsystem block is on one layer and the blocks that make up the subsystem are on another.
Keeps functionally related blocks together.
Helps reduce the number of blocks displayed in your model window.
Establishes an interface with inputs and outputs.

When you make a copy of a subsystem, that copy is independent of the source subsystem. To reuse the contents of a subsystem across a model or across models, consider referenced subsystems, referenced models, or subsystems linked to a block in a custom library. For more information, see Explore Types of Model Components.

A subsystem can be virtual or nonvirtual. A virtual subsystem provides graphical hierarchy in a model. A nonvirtual subsystem provides graphical hierarchy and executes as a unit within a model.

Blocks

Subsystem

Group blocks to create model hierarchy

Functions

expand all

Subsystem Functions

`Simulink.BlockDiagram.createSubsystem`	Create subsystem containing specified set of blocks
`Simulink.BlockDiagram.copyContentsToSubsystem`	Copy graphical contents from system to empty subsystem
`Simulink.BlockDiagram.expandSubsystem`	Replace subsystem with subsystem contents
`Simulink.SubSystem.convertToModelReference`	Convert subsystems to models
`Simulink.SubSystem.copyContentsToBlockDiagram`	Copy graphical contents from subsystem to another model
`Simulink.SubSystem.deleteContents`	Delete contents of subsystem

Subsystem Reference Functions

`Simulink.SubsystemReference.convertSubsystemToSubsystemReference`	Convert Subsystem block to Subsystem Reference block (Since R2022a)
`Simulink.SubsystemReference.convertSubsystemReferenceBlockToSubsystem`	Convert Subsystem Reference block to Subsystem block (Since R2022a)
`Simulink.SubsystemReference.convertAllSubsystemReferenceBlocksToSubsystem`	Convert all Subsystem Reference blocks to Subsystem blocks (Since R2022a)
`Simulink.SubsystemReference.getAllInstances`	Return all Subsystem Reference blocks in model (Since R2022a)
`Simulink.SubsystemReference.getActiveInstances`	Return active instances of subsystem reference (Since R2022a)
`Simulink.SubsystemReference.getAllDirtyInstances`	Return subsystem files referenced in model that are currently being edited (Since R2022a)
`Simulink.SubsystemReference.getNearestParentSubsystemReferenceBlock`	Return nearest parent Subsystem Reference block for specified block (Since R2022a)
`Simulink.SubsystemReference.getAllReferencedSubsystemBlockDiagrams`	Return all subsystem files referenced in model (Since R2022a)
`Simulink.SubsystemReference.getSystemOwningTheLock`	Return subsystem reference instance that has acquired lock for editing (Since R2022a)
`Simulink.SubsystemReference.isSystemLocked`	Check if subsystem file is locked due to edit or update (Since R2022a)
`Simulink.SubsystemReference.generateSignatures`	Generate unit test signatures of subsystem file (Since R2023a)
`Simulink.SubsystemReference.getUnitTestNames`	Return names of unit tests of subsystem file (Since R2023a)
`Simulink.SubsystemReference.removeSignatures`	Remove previously generated unit test signatures of subsystem file (Since R2023a)
`Simulink.SubsystemReference.showSignatureDiffDialogForSS`	Display differences in signatures of two Subsystem blocks (Since R2023a)
`Simulink.SubsystemReference.showSignatureDiffDialogForUnitTests`	Display differences in signatures of Subsystem Reference block in model with unit test signatures of subsystem file (Since R2023a)

Tools

Model Reference Conversion Advisor	Convert subsystems to referenced models
Referenced Files Pane	View, save, and close referenced subsystems and models (Since R2020b)
Component Interface View	Display component interfaces to trace port connections and author ports

Topics

Subsystems

Explore Types of Subsystems
Decide among virtual and nonvirtual subsystems, including conditionally executed subsystems.
Group Blocks into Subsystems
Use subsystems to organize large models.
Expand Subsystem Contents
Flatten a model hierarchy by bringing the contents of a subsystem up one level.
Connect Subsystems
Add ports to subsystems and configure port labels.
Navigate Model Hierarchy
Navigate model hierarchy using the Explorer Bar and Model Browser.
Preview Content of Model Components
Display representation of block contents on the face of a block.
Trace Connections and Author Ports Using Component Interface View
Display component interfaces to trace port connections and author ports.

Subsystem References

Create and Use Referenced Subsystems in Models
Reference, reuse, and manage subsystems stored in separate files.
Convert Subsystem to a Referenced Subsystem
This example shows how you can convert a Subsystem block in a model or library to a Subsystem Reference block.
Mask a Subsystem File
Use system mask to customize each instance of a referenced subsystem.
Manage Subsystem Reference Data Using External Data Sources
Use Simulink^® data dictionary and MAT files for managing subsystem reference data.
Define Subsystem Reference Interfaces Using Test Harnesses and Generate Reusable Code
This example shows how to define interfaces and generate reusable code for subsystem reference, and how to verify that a model uses the subsystem reference correctly.
Change Subsystem Reference Component Dynamically Using InitFcn
This example shows how to dynamically change the subsystem reference component using the Initialization Function.
Control Subsystem Reference Programmatically
Find, replace, and check referenced subsystems in models.

Related Information

Creating and Masking Subsystems (3 min, 50 sec)
Conditionally Executed Subsystems and Models
Iterator Subsystems
Component-Based Modeling
Collaborative Modeling