select bus elements programmatically

Question

I have signals in a SIMULINK bus and I would like to select specific signals from it. The issue is that I want to run an initialization script that will decide which subset of signals to select. I see that you can select bus signals manually via the bus selector block. Is there any way to perform this function programmatically?

John Michell · Accepted Answer

Use set_param on the 'OutputSignals' Parameter
The key parameter for a Bus Selector block is OutputSignals, which specifies the selected elements as a comma-separated string of element names (hierarchical names for nested buses, e.g., 'bus1.signalA,bus2.nestedSignal').
Example Code
Assume your model is loaded, and the Bus Selector block path is 'myModel/mySubsystem/BusSelector1'.


Get current selected signals (optional, to build upon existing):



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currentSignals = get_param('myModel/mySubsystem/BusSelector1', 'OutputSignals');
disp(currentSignals);  % e.g., 'signal1,signal2,nested.busSignal'

 

 




Set new selected signals (overwrites all; specify the full list):



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set_param('myModel/mySubsystem/BusSelector1', 'OutputSignals', 'signalA,signalB,nestedBus.signalX');

 

 



This updates the block: adds/removes output ports accordingly.
Element names must match exactly what's available in the input bus (case-sensitive, including hierarchy like 'topBus.subBus.element').
For a single element: 'mySignal'
For none (clear all): '' (empty string)



To add to existing without overwriting:



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current = get_param('myModel/mySubsystem/BusSelector1', 'OutputSignals');
newList = [current ',newSignal'];  % Append (add comma if current not empty)
if ~isempty(current)
    newList = [current ',newSignal'];
else
    newList = 'newSignal';
end
set_param('myModel/mySubsystem/BusSelector1', 'OutputSignals', newList);

 

 




Additional Options

Output as virtual bus: If you want selected elements grouped into one virtual bus output port:



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set_param('myModel/mySubsystem/BusSelector1', 'OutputAsBus', 'on');  % or 'off' for separate ports

 

 



After setting, update the model diagram if needed:



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set_param('myModel', 'SimulationCommand', 'update');

select bus elements programmatically

Use set_param on the 'OutputSignals' Parameter

Example Code

Additional Options

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