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Custom Components

Write Simscape™ files to represent custom components

The Simscape language lets you define custom components as textual files, complete with parameterization, physical connections, and underlying equations. Topics on this page provide detailed information on declaring component parameters, variables, and connections. For other aspects of defining custom components, see Component Equations, Discrete Events and Mode Charts, and Composite Components.

To get started with writing custom components, see Creating Custom Components, which provides an overview of the general workflow. At the bottom of this page, topics listed under Reference Application Components provide complete component examples with detailed explanations that illustrate the techniques used in each case.

Language Syntax

annotationsControl appearance of Simscape block based on the component
branchesEstablish relationship between component Through variables and nodes
componentComponent model keywords
inputsDefine component inputs, that is, Physical Signal input ports of block
nodesDefine component nodes, that is, conserving ports of block
outputsDefine component outputs, that is, Physical Signal output ports of block
parametersSpecify component parameters
variablesDefine domain or component variables


Basic Techniques

Creating Custom Components

Component types, file structure, high-level workflow.

Attribute Lists

Model attributes and member attributes used in Simscape language.

Declarations and Branches

Declaring Domains and Components

Declaration section of domain and component files: purpose, definitions, rules, member summaries.

Declare a Spring Component

The following diagram shows a network representation of a mass-spring-damper system, consisting of four components (mass, spring, damper, and reference) in a mechanical rotational domain.

Declare Component Parameters

Component parameters let you specify adjustable parameters for the Simscape block generated from the component file.

Declare Component Nodes

Component nodes define the conserving ports of a Simscape block generated from the component file.

Declare Component Inputs and Outputs

In addition to conserving ports, Simscape blocks can contain Physical Signal input and output ports, directional ports that carry signals with associated units.

Declare Component Variables

When you declare Through and Across variables in a component, you are essentially creating instances of domain Through and Across variables.

Define Relationship Between Component Variables and Nodes

How to connect Through and Across variables declared in a component file to the domain Through and Across variables.

Declaration Functions

Use MATLAB® functions to compute derived parameter values or initialize variables.

Component Variants

Defining Component Variants

Use conditional sections to define variants within component file.

Defining Conditional Visibility of Component Members

Use annotation section to define conditional visibility of ports and parameters for component variants.

Advanced Techniques


Specify a discrete set of acceptable values for parameters and event variables.

Subclassing and Inheritance

Subclassing allows you to build component models based on other component models by extension.

Reference Application Components

Model Linear Resistor in Simscape Language

Overview of how modeling in Simscape language works, using a linear resistor as an example.

Mechanical Component — Spring

The following file, spring.ssc, implements a component called spring.

Electrical Component — Ideal Capacitor

The following file, ideal_capacitor.ssc, implements a component called ideal_capacitor.

No-Flow Component — Voltage Sensor

The following file, voltage_sensor.ssc, implements a component called voltage_sensor.

Grounding Component — Electrical Reference

The easiest way to implement a grounding component is to use a connection to an implicit reference node.

Composite Component — DC Motor

This example shows how to implement a DC motor model by means of a composite component.

Triggered Delay Component

This example shows how to implement a triggered delay component.

Enabled Component

This example shows how to implement a component similar to a Simulink® enabled subsystem.

Switch with Hysteresis

This example shows how to model a component by using mode charts and enumerations.

Component Variants — Series RLC Branch

This example shows how to implement variants within a component file by using conditional sections.

Component Variants — Thermal Resistor

This example shows how to implement conditional visibility of component ports, parameters, variables, and a conditional custom block icon.