How can I increase a count in the while iterator block?

I am trying to run a whilte iterator block for the convergence of a variable, but this variable is not decreasing at all.

The goal is to reach at Display3 a value higher than 7.94 (Psep) and Display1 to show a value lesser than 31.

Could you help with this matter?

Thanks in advance.

[Mathieu NOE]

hello

1/ I assume that this part

is inside a while iterator subsystem While Iterator Subsystem - Repeat subsystem execution during simulation time step while logical expression is true - Simulink

2 / Psep seems to be a constant = 7.94, so I don't see how it could evolve ...

3/ there is nothing that increments (counter) in your code . The while iterator block output should eventually be used to drive a counter which output then must be fed at the same firts add block (neg input) . I would also recommend to convert the while block output from logicl to numerical if you use it afterwards to do numerical operations

all the best

[Walter Roberson]

The output of the comparison to zero is being fed into the Add block where it is being subtracted. At best that would result in subtracting 1 each iteration; at worst it would result in subtracting 0 each iteration.

[Carlos]

Hi, thanks for your time to analyse this problem.

1- You are right, it is inside a While iterator subsystem

2- You are right, Psep is a constant but it is only a value for comparison, the real thing is that I need that Fcn P be greater than Psep.

It comes from a larger system in which I already know for certain that Fcn P is lower than Psep. (the display block after the while iterator block is not the answer I am looking form).

That is why, inside the while iterator system, I am looking for lowering In1 by 1 each time the while iterator is running in order to have a Fcn P greater than Psep.

3- Again you are right. I am not really certain in the use of the while iterator block in order to control what I am planning to do. Could you tell me how I am supposed to do that? or give me a reference or example that I can use as a guide to do the job.

Thanks again.

[Carlos]

Hi, I appreciate your time to analyse this problem.

You are right. it comes from a larger system and I already know for certain that Fcn P is lower than Psep and I am looking for lowering In1 by 1 each time the iterator is running in order to have a Fcn P greater than Psep. When Fcn P becomes greater than Psep, I expect to finish the cycle.

[Mathieu NOE]

hello

can you share a working / simplified simulink file ?

I'll try to fix the problem

[Carlos]

hi.

Thanks very much for your interest in this matter.

I have been working based on an example and have adapted it to the problem itself.

I send the answer I have come across.

While_iterator_block

Thanks again.

[Mathieu NOE]

I think the link is broken

can you double check ?

[Carlos]

Hello again.

Sorry for the delay.

I was trying the hyperlink and the attachment icons, but they are not running as I expected.

I insert this diagram to ilustrate the flow.

The Fxn WHP2 block have this in it:

33.85269581 - 1.47824232 * u + 0.02529957 * u * u - 0.00014113 * u * u * u

After that, it runs well when I tried only one value from % Apert block. With more values, it doesn't run well.

I am looking for to use an algebraic constraint block afterwards outside this block for convergence, but if this block does not work for various data points, I get stuck.

If you could advise about this, I really appreciate.

[Mathieu NOE]

is the simulink file to big to be attached with the paper clip button ?

[Carlos]

The antivirus is probably blocking the attachment function.

I will try later.

[Carlos]

Hello again.

Here is the attachment.

[Mathieu NOE]

can you save it in Simulink Version 25.1 (matlab R2025a) please ?

[Walter Roberson]

R2025a version of the file enclosed.

Note: you could have opened the file in MATLAB Online and saved it there.

[Carlos]

Thanks very much for your suggestions.