How can I ignore or disconnect a node in a custom Simscape component?

I am building a custom Simscape component which models a valve, and I need a way to ignore or disconnect one of the nodes based on the state of the block. For example, if the valve has 3 connections (A, B, C), when the valve is in the state where the fluid flows from A to C, B should be ignored or disconnected.

How can I conditionally ignore a port in my Simscape component?

Answer 1

[MathWorks Support Team]

One approach you could consider in order to "ignore" a node would be to make the port connections conditional. To do so, place the "connections" block inside of an if/else block that decides which connections to make based on the valve status.

This could look something like the following code:

if is_AC_flow
    connections
        connect(A, valve_A.port)
        connect(C, valve_C.port)
    end
else
    connections
        connect(A, valve_A.port)
        connect(B, valve_B.port)
    end
end

The other equations in the component would need to be updated to reflect the conditional connections, but this approach would allow you to selectively disconnect the B and C ports.