Comments for Guy and Seth on Simulink

Comment on Creating Your Own Block With Continuous States (MATLAB S-Function) by AJ

AJ — Wed, 22 May 2013 11:27:47 +0000

This article really helped! Defo big thanks to you for this insightful information. Keep up the good work!

Comment on Where Does That Variable Come From? by Seth

Seth — Tue, 21 May 2013 18:35:01 +0000

@Tony, The variable k is in the Model Workspace. It was created interactively through the Model Explorer, and is saved into the MDL file. You can also programmatically initialize the model workspace using MATLAB Commands.

Comment on Where Does That Variable Come From? by Tony

Tony — Tue, 21 May 2013 18:20:20 +0000

Hi Seth,

Excellent blog. Full of valuable tips.
Can you explain which part of your model set k=200 into the model workspace?
I was able to find a=10 and m=10 in Model properties – Callbacks – PreLoadFcn. I was able to find other mask parameter settings for m=3000, k=50 000. But I was not able to find where did you set k=200.
Am I blind, stupid or both?

Comment on How did I get an algebraic loop error, when the diagnostic was set to warning? by Mike Tesfaye

Mike Tesfaye — Mon, 20 May 2013 17:48:03 +0000

Me too Like Paul J. I had a case where an algebraic loop was reported when a gain block was set to something other than 1; and I just had a problem where an algebraic loop error was reported in a very simple model where there is a transfer between two states (stateflow).

Comment on Sum Block: Round or Rectangular? by Issopui

Issopui — Fri, 17 May 2013 13:52:40 +0000

Hello guys,

I’m very sorry for my comment which may not be related to the topic but it is related to simulink blockset.

I am working on a small project using computer vision sytem toolbox. I have 3 images which I need to convert to grayscale and then subtract image2 from image one do the binary thresholding and finanlly the AND logic gate to find the final position.

My question is “Which blockset should I use to subtract two grayscale images?” I have tried the subtract blockset from math operation but my output image look exactly like the one I got after thresholding.

Please guys help me being trying for weeks now. What is the proper blockset to be used for two grayscale subtraction?

I’m sorry for my long message. Wish u guys will me

Thanks in Advance

Issopui

Comment on Sum Block: Round or Rectangular? by Paul

Paul — Wed, 15 May 2013 09:45:59 +0000

@Guy
These duplicate blocks should be removed in a future release IMHO.
It’s just not good practice to have different blocks doing the same thing when the variations could be achieved with mask settings.
If you are concerned with people still looking for the old blocks, there are many solutions to this. For example, I often use the search field to say find an “add block”. You could update the search terms so that “sum” also gives the “add” block result.
Other more complex solutions exist, such as retaining the original blocks, but having them immediately convert to the “add” block on placement in the model…
Ultimately, I there should not be multiple blocks for the same function. And any time you are using historical convention to justify something concerns me! It means you are being held back in progress…

Comment on How to customize the Simulink Scope – Take 2 by N. Amann

N. Amann — Tue, 14 May 2013 15:39:31 +0000

In earlier versions, one could set in the startup.m file a line like set(0,’defaultLineLineWidth’,2.0)

This made that there were thick lines in all plots and also in scopes. With the new scope graphics editor, this does not work any more for scopes. Is there a way to tell Simulink in advance to have thick lines in all scopes?

Comment on Sum Block: Round or Rectangular? by Guy Rouleau

Guy Rouleau — Mon, 13 May 2013 15:42:29 +0000

@Paul, Having multiple instances of the same block with different settings is something relatively common in the Simulink Library Browser. For many users, it seems to make it easier to find what they are looking for.

For example:

- The Math section of the library contains 4 instances of the Sum block: Sum, Add, Subtract and Sum of Elements. It also contains 3 instances of the Product block: Product, Divide and Product of Elements

- Resettable Delay and Variable Integer Delay are both instances of the generic Delay block.

- Lookup Tables blocks: 1-D, 2-D and N-D are the same block with different settings.

- Vector Concatenate and Matrix Concatenate

Comment on Sum Block: Round or Rectangular? by Ryan

Ryan — Mon, 13 May 2013 14:09:50 +0000

Great post. Whenever I receive a model with a square sum for a control system I have to change them over to circular. Nothing technically wrong, but I like the relationship between circular summing junctions and control system diagrams.

Comment on Sum Block: Round or Rectangular? by Paul

Paul — Mon, 13 May 2013 05:23:35 +0000

Yes it’s pretty silly to still be including two separate blocks in the library when there is no functional difference between them. It can even be confusing to new users. Back in the day, I used to think the round block should be used for continuous applications and the square block for discrete. Really, they should be combines, and the visual preference relegated to being a simple mask parameter…