Guy on Simulink

Simulink & Model-Based Design

My Mental Model of a Model

When you are new to something, it always helps to get a
mental picture of how that something works.  Since I learned Simulink over 10
years ago, I have developed my own mental model of Simulink models.  Today I
want to present a mental model for the three basic components in Simulink block
diagrams, ports, blocks and signals.

Something Familiar

A good mental model is something to which you are already
familiar.  I like to compare Simulink diagrams to programs written in a
procedural language like MATLAB or C.  My favorite is MATLAB, so that is
usually how I think.


Ports are the input and output arguments for the function.


When I think about blocks, I think of them as algorithmic
components of the programs.  A block like the Gain or Product is a function
that operates on inputs and produces an output.


Signal lines pass the value output from one block to the
next block.  I think of signal lines as the variables in a program.

A Simulink block diagram and corresponding M-code to illustrate my mental model.

Generating Code

With my intuition in hand, I read the generated code so I
can compare and refine my mental model.  The result is here:

The generated code from the model.  Pretty close to the mental model.

In this case, I made a couple tweaks to the code generation
settings for readability and interface. 

What do you think?

How does your mental model of a block diagram compare to
mine?  Leave a comment
and share it with me.



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