Guy and Seth on Simulink

June 26th, 2009

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

Ports are the input and output arguments for the function.

Blocks

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.

Signals

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 here and share it with me.

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By Seth Popinchalk

20:09 UTC | Posted in Code Generation, Fundamentals, Modeling, Real-Time Workshop | Permalink | 2 Comments »

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2 Responses to “My Mental Model of a Model”

  1. M.tamilselvan replied on June 29th, 2009 at 10:50 UTC : 
    this piece of snippet is short and crisp,need to post more mental model strutures in depth possible with optimization issuses.
  2. Jarrod Rivituso replied on July 2nd, 2009 at 17:05 UTC :

    “I think of signal lines as the variables in a program.”

    I say the exact same thing every time I teach our Simulink courses :)

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About

Guy Rouleau and Seth Popinchalk are Application Engineers for MathWorks. They write here about Simulink and other MathWorks tools used in Model-Based Design.

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