Reverting Referenced Subsystems back to normal Subsystems

hament_singh asked: 2021-09-28 subsystem reference , expand subsystem

Learn how to revert referenced subsystems back to normal subsystems in Simulink with this helpful resource. Solve referencing issues & simplify your models. Rea

Expert Answer

John Williams answered . 2025-07-30 22:09:32

I can confirm that the feature to expand referenced subsystems was removed in R2020a. So, it looks like the best way around is to copy the referenced subsystem to all locations. This can be done using the simulink.blockdiagram.copycontentstosubsystem command. I suppose replace_block will be useful along with it but I haven't tried it out.

I've written a script to demonstrate how you could go about this. I've used add_line and delete_line instead to reconnect the subsystems.

And here's the script that does that:

refSubsystem = 'subsys20b';
modelName = 'modelRefSubsys20b';
open_system(modelName);

oldBlock = [ modelName '/Subsystem Reference'];
newBlock = [ modelName '/subsystem'];

% create a copy of the referenced subsystem
add_block('built-in/Subsystem', newBlock)
Simulink.BlockDiagram.copyContentsToSubsystem(refSubsystem, newBlock)

% Retrieve useful info from the old block
t1 = get_param(oldBlock, 'Portconnectivity');
t2 = get_param(oldBlock, 'PortHandles');
t3 = get_param(newBlock, 'PortHandles');

% delete old lines
h = get_param(oldBlock, 'LineHandles');
ni = numel(h.Inport);
no = numel(h.Outport);
delete_line(h.Inport);
delete_line(h.Outport);

% create connections to new block
for i=1:numel(t2.Inport)
    srcBkhdl = t1(i).SrcBlock; % source block handle
    srcNm = getfullname(srcBkhdl); % source block name
    srcBkPts = get_param(srcNm, 'PortHandles'); % source block port handles
    srcPt = srcBkPts.Outport(t1(i).SrcPort+1); % source port
    dstPt = t3.Inport(i); % destination port
    add_line(modelName, srcPt, dstPt);
end

% create connections from new block
for i=1:numel(t2.Outport)
    dstBkhdl = t1(ni+i).DstBlock; % dest block handle
    dstNm = getfullname(dstBkhdl); % dest block name
    dstBkPts = get_param(dstNm, 'PortHandles'); % dest block port handles
    dstPt = dstBkPts.Inport(t1(ni+i).DstPort+1); % dest port
    srcPt = t3.Outport(i); % src port
    add_line(modelName, srcPt, dstPt);
end

% copy to same position
pos = get_param(oldBlock, 'position');
set_param(newBlock, 'position', pos);

% remove old block
delete_block(oldBlock);

% save changes
save_system(modelName);

% replace_block might work.. Haven't tried
% replace_block(modelName, 'Subsystem Reference', 'subsystem')

Some notes:

I do not regularly edit models programmatically. So, my approach might be inefficient/roundabout. This is just a suggestion. You can use this as a reference to get started.