How to create input and output port in Simulink and then connect them using Matlab script

I want to create input and output ports in Simulink and then connect them using Matlab script to begin with iplementation of something bigger.

I tried searching on Google and Matlab central but couldnt find the relevant information.

Can you guide me to relevant links to begin with and some commands which will help me , a small sample script will be of great help.

Also would it be possible to add a multiplication block in simulink which takes input from two inports and then send output to a display block and also an output port ?

Answer 1

[Luca Ferro]

Here is a link to the relevant mathworks documentation: https://ch.mathworks.com/help/simulink/ug/approach-modeling-programmatically.html

In any case, adding blocks is quite simple. The function is add_block(librarySource,simulinnkDestination):

librarySource is from where the block comes, you can either search the source of any simulink block in the documentation or in simulink itself go to the library browser (under simulation ribbon) and hoover on the block you wish to add to be shown the source.

simulinkDestination is the path where you want to block to be created. Note that the name MUST be unique.

In your case:

add_block('simulink/Commonly Used Blocks/In1','yourSimulinkProjectName/yourInputName'); %for inports

add_block('simulink/Commonly Used Blocks/Out1','yourSimulinkProjectName/yourOutputName'); %for outports

add_block('simulink/Commonly Used Blocks/Product','yourSimulinkProjectName/product1'); %for multiplication

add_block('simulink/Commonly Used Blocks/Scope','yourSimulinkProjectName/scope1'); %for display

for adding lines there are several mehods you could use, the one i like is using port handles which are numbers that identifies the ports of each block. This is valid for every block, here i'll show you for the before said input and product:

inputHndl = get_param('yourSimulinkProjectName/yourInputName','PortHandles');

productHndl = get_param('yourSimulinkProjectName/product1','PortHandles');

The first string is the path to the block, the second is the property you want to get. The output is a struct of which the two fields you are mostly interested into are .Inport and .Outport.

Now that you have the handles you can connect the blocks:

add_line('yourSimulinkProjectName',inputHndl.Outport(1),productHndl.Inport(1),,'autorouting','smart')

The first string is the project name, and note that the handles have numbers. For the input we only have one because there is only one port, so 1 is the only value we could choose. For the product there is 2 inports, i choose one but it could have been productHndl.Inport(2) if you wished. The autorouting is just for practical purposes but it's totally optional, it just avoids overlapping.

Repeat the same for every block and there you have the connection.

At the end i would suggest to use this command so that it manages the positioning of the blocks automatically. Otherwise you would have to move them programmatically using set_param() but it can be a pain.

Simulink.BlockDiagram.arrangeSystem('yourSimulinkProjectName')

For the script, try it yourself before and get back at me if you have any issues :)

[ANKUR WADHWA]

Thank you Luca for the link and the relevant inforamation.

[ANKUR WADHWA]

Hi @Luca Ferro I was trying to find out if there is a way to directly connect the ports based on the handle associated with the block and then name the signal ?

For now I am using the below commands to achieve the same

%  Adding ports or blocks to Model and saving their handles in variables , though I am not using the handles as of now
speedhandle = add_block('simulink/Commonly Used Blocks/In1','ProgrammaticSimulink/speed'); %for inports

A new block named 'ProgrammaticSimulink/speed' cannot be added

distancehandle = add_block('simulink/Commonly Used Blocks/Out1','ProgrammaticSimulink/distance'); %for outports

% Get PortHandles parameters
inputHndlspeed = get_param('ProgrammaticSimulink/speed','PortHandles');
outHndldistance = get_param('ProgrammaticSimulink/distance','PortHandles');

%  Add line between the ports
add_line('ProgrammaticSimulink',inputHndlspeed.Outport(1),outHndldistance.Inport(1));

% Name or rename the line connected between the ports
speedline = get_param(inputHndlspeed.Outport,'Line');
set_param(speedline,'Name','speed');

Is there any way this can be achieved in an easier manner with less number of commands and concise commands.

also many a times I run this afresh I get error "A new block named 'ProgrammaticSimulink/speed' cannot be added" even though the model is not having existing port or block named speed.

[Luca Ferro]

yes there is shorter method that relies on block names, in your case:

add_line('ProgrammaticsSimulink','speed/1','distance/1');

as you can see it strictly requires you to know the block path and name. The first block is always the source, the second the sink. '/1' means it is connecting port 1 (it may be relevant for block with multiple I/Os.

The error is thrown because there is already a block named speed in the model, as you correctly identified. If you are running the script multiple times it is a good idea to always check that the model is clean by not saving it after generation and be sure that the memory is clean by closing them with bdclose('all') command.

If you want to check if a block is already present in your model you can run this:

allBlocks=getfullname(find_system('tmpp','FindAll','on'))

and check visually, or if your model has a lot of blocks you could parse the output by searching for the string 'speed' in the cell array.

[ANKUR WADHWA]

Thanks for the new command @Luca Ferro , in the code snippet I shared in previous comment I am renaming the signal line between the ports once the connection is made which I am doing by

% Name or rename the line connected between the ports
speedline = get_param(inputHndlspeed.Outport,'Line');
set_param(speedline,'Name','speed');

I was trying to find a way where this can be done without creating intermediate variables and can be done while creating the connection between the ports. Is there a possible way to achieve the same

Or we have to mandatorily write additional commands for naming the signal line only, post creating the connection.

Where we have to first get the port or block handle and then get Line properties separately and then use the "Name" attribute to name the signal

[Luca Ferro]

as you can see from the get_param, the line is not an object himself but it refers to the outport from which is originated. I'm not aware of a way to use a one-liner to set the name. If there is a way it will come in the shape of name-value options on the creation of the block (speed in your case). You can search for block specific parameters here:

https://www.mathworks.com/help/simulink/slref/block-specific-parameters.html