the scope in simulink doesn't show some specific signal.

the signal after the block of intergration is unplotted by scope who can be used to probe the other signals that I am sure the scope is good.

and the signal unplotted as well as the signal processed from the former one cann't be plotted either.

[Sahas]

Hi @ED,

Can you share the model file? It would help me undertand the issue and assist you better.

[ED]

the scope is blank with some signal, but normal with other signals.

I browse online, someone suggests it has something to do with GPU which I really doubt for it seemingly depents on the signal probed.

Answer 1

[Jatin]

Hi @ED,

There can be few reasons for the signal not being plotted in the scope block, kindly see if the following points are helpful to you:

1. Make sure the scope block has enough input ports to accommodate all signals you want to plot. You can specify the number of ports in scope block.
2. You can adjust the Y-axis limits of the scope to ensure the signal is within the visible range.

If you are sure that the scope block is configured properly, then you can make sure the below points are covered:

1. If the system has discontinuities, you can enable zero-crossing detection for better accuracy.
2. Ensure simulation time is sufficient to capture signal changes, also check the step size, too large of a step size might miss signal transitions.

If everything looks fine, kindly inspect the signal using Display block or Simulation Data Inspector for any unexpected behaviour.

You can also refer the documentation below for more details on ‘Scope block’:

https://www.mathworks.com/help/simulink/ug/simulation-data-display-and-capture-using-scopes.html

Hope this Helps!

[ED]

Hi Jatin Singh, Thank you for the methods.

Anyway, I fixed it.

The issue was caused by the operation of division by signal which is zero at time 0 before it reached out to the block of integrator.

What is weird is why the matlab didn't report the error as well as stop immediately other than processed to the end.

[Sahas]

Hi @ED,

That is a very interesting find.

As per my understanding, it being casused due to the input of the integration block was 0. Am I right? Can you provide more details on this. Thanks.

[Sam Chak]

Hi Ed, the reason is probably because some functions at a specific point where the division by zero occurs, is indeterminate 0/0 but it has a limit.

You probably remember L'Hôpital's rule in the Calculus class...

[ED]

Hi Both：

It happens at time 0 with 0/0, I really get confused that the model configuration has default of none for inf and NaN block out other than warning or even error. After switched into error, it makes sense by stopping simulation with location of the issue highlighted.