Is there a built-in mechanism in System Composer/Simulink to activate/deactivate components based on state logic (e.g., via ports or triggers)?

Question:

I am working on a System Composer architecture model where I need to implement dynamic component activation based on state machine logic. The scenario is as follows:

1. Components:

• 1 State Machine Component (e.g., StateController)
• 3 State-Specific Components (e.g., StateA, StateB, StateC).

1. Goal:

• The StateController determines the current state (e.g., State A/B/C).
• Only the component corresponding to the active state (e.g., StateA when in State A) should be enabled/executed, while others remain inactive.

1. Key Challenges:

• How to design the architecture to enable/disable components dynamically without physical signal connections?
• Are there recommended patterns in System Composer for this use case (e.g., using service ports, Simulink Functions, or enabled subsystems)?
• How to ensure clean transitions between states (e.g., avoiding conflicts when switching states)?

Example Workflow:

• If StateController transitions to State A:
• Enable StateA component.
• Disable StateB and StateC.
• Repeat similarly for other states.

Specific Queries:

1. Is there a built-in mechanism in System Composer/Simulink to activate/deactivate components based on state logic (e.g., via ports or triggers)?
2. What is the best way to implement this pattern? Options I’ve considered:

• Enabled Subsystems with control signals from the state machine.
• Service Ports/External Function Calls to start/stop components.
• Simulink Functions triggered by state transitions.

1. Are there examples or documentation for similar dynamic component management?

Thank you for your guidance!

Answer 1

[Josh Kahn]

Hi @lei,

Yes! It looks like you are trying to create a Service Oriented Architecture.

You can do it in System Composer with the Software Architecture Template one of two ways:

First, you can using the Functions Editor to add functions to your components. These can be called from a Stateflow scheduler as shown in this example:

https://www.mathworks.com/help/systemcomposer/ug/modeling-software-architecture-of-a-throtlle-position-control-system.html

Alternatively, you can use Client-Server ports as shown in the example below and similar to above, send the calls from the client by using stateflow:

https://www.mathworks.com/help/systemcomposer/ug/simulate-asynchronous-interfaces-for-headlights.html

I also have a livestream discusing that topic here:

https://www.youtube.com/watch?v=RsB6ARyflIQ

Let me know if you need any more help with this!

Josh

[lei]

Thank you very much, this is exactly what I was looking for.

Answer 2

[Divyanshu]

Hello @lei,

I am not sure of System Composer specifically, but based on the condition specified in the base workspace you can enable one subsystem and other subsystems would be disabled automatically. This can be achieved by using a block called 'Variant Subsystem' in the simulink.

This block has a parameter, where you can specify certain condition corresponding to each subsystem of the block and if a particular condition is true then only corresponding subsystem would be active.

You can read about this block in the following documentation:

https://www.mathworks.com/help/simulink/slref/variantsubsystem.html

Additionally, you can refer the following example for better understanding:

https://www.mathworks.com/help/simulink/var/variant-subsystems.html

[lei]

Thank you very much, I will learn the variant subsystems you mentioned.