how to define the output of a system object as a bus element in simulink?

I am using matlab system objects (SysOb) in simulink. I want to have the outputs assigned to a bus element. I can do this with a Subsystem and want the same behaviour for a SysOb. I tried creating an output struct for the SysOb but when I connect this output to a bus selector there are no signals (fields?) to pick. I assume that the SysOb should be at least as good as a Subsystem.

[Manikanta Aditya]

Check these:

• Specify Bus Properties with Bus Objects - MATLAB & Simulink (mathworks.com)
• Specify output of external port - Simulink (mathworks.com)

[dale finney]

did you just google my question? if so, not helpful

I read item 1 and did not find anything specific to my problem

I had already tried item 2 but it doesn't work for me. This works when one assigns signals to a bus creator and then to an output bus element inside a subsystem. As I mentioned in my original question, subsystems are not a problem.

[Manikanta Aditya]

Oh Alright, I just shared the references hoping they can guide you to some extent.

Answer 1

[Mark McBroom]

1. create a Simulink Bus with the same layout as the MATLAB structure you are creating in your system object.
2. Set the type of the system object output to be this simulink bus using the getOutputDataTypeImpl() method:

https://www.mathworks.com/help/matlab/ref/matlab.system.getoutputdatatypeimpl.html

Answer 2

[dale finney]

thanks for your reply.

For Item 2 I have the something like following but with many more fields:

function out = getOutputDataTypeImpl(obj)

[out.A, out.B, out.C, out.D] = deal("logical");

end

For item 1, I still don't understand. I have to 'layout' the bus selector before I use it? normally simulink will populate the list of available signals in the bus. Is it different?