I dont know the exact rationale behind it, but in my use case, nested model(s), i.e. input propagation, especially in schematic view.

You have a model A that have an input input_a nested/used insiede model B and model B itself is used inside a top model C. inorder to connect model C to input_a you have to create some input port to allow the value to be passed from C via B to A.

e.g.:

connect(modelA.input_a, modelB.input_ba) ; //connection between B and A inside modelB



connenct(modelC.someValue, modelB.input_ba) ; //connection between some value to B inside model C

of course you can write your own under equation section in text view such as:

connecnt(modelC.someValue, modelB.modelA.input_a); //connection between modelA and someValue in model C

but sometimes user only want to do the modelling through schematic/diagram view and thats why it is possible to connect two input ports together.

at least that is MY reasoning.

cheers

OK, thanks, that sounds reasonable.

Do you know any way to restrict possible connections to input-to-output connections only (so that input-input (or output-output) connections will not be allowed)?

MP wrote:

Do you know any way to restrict possible connections to input-to-output connections only (so that input-input (or output-output) connections will not be allowed)?

Why would you restrict the connection?

I dont have any idea how that would be done... normally you can use assert to check condition regarding parameter (i.e. check if a parameter within allowed limit), but i've never done a connectuion type checking.

If you could share your use case or a minimum working example, it would help.

model Test

Modelica.Blocks.Interfaces.RealInput input1;

Modelica.Blocks.Interfaces.RealInput input2;

Modelica.Blocks.Interfaces.RealOutput output1;

equation

  connect(input1, input2);

end Test;

failed the translation

[2] 16:09:22 Symbolic Error

[Test: 8:3-8:26]: Found equation without time-dependent variables: input1 = input2



[3] 16:09:22 Translation Error

[C:/dev/OM64bit/OMCompiler/Compiler/BackEnd/ResolveLoops.mo: 295:9-295:86]: Internal error function resolveLoops_cutNodes failed



[4] 16:09:22 Translation Error

Internal error IndexReduction.pantelidesIndexReduction failed! Found empty set of continuous equations. Use -d=bltdump to get more information.



[5] 16:09:22 Translation Error

Internal error Transformation Module PFPlusExt index Reduction Method Pantelides failed!