Converting comma to dot in app designer

Hi, i'm trying to convert a number with comma to number with dot, like "0,25" to "0.25"

In the past i used in GUIDE the follow structure and always worked just fine:

function calcular_cc_geradorButtonPushed(app, event)
    escolha_lista_curto = app.escolha_curto.Value
    X1_pu = str2double(strrep(app.Z_x1.Value,',','.'));
    if strcmp(escolha_lista_curto,'Ex: 1Ø')
        app.z_base.Value=X1_pu;
    end
end

But now, i'm always getting the same error:

'Value' must be a double scalar within the range of 'Limits'.

What should i do?

Thanks

[Stephen23]

@Jucimar Carpe: please show us the complete error message. This means all of the red text.

[Jucimar Carpe]

Hi Stephen, sorry...my mistake.

Here is the complete error message:

----------

Error using matlab.ui.control.internal.model.AbstractNumericComponent/set.Value (line 184)

'Value' must be a double scalar within the range of 'Limits'.

-----

Just for your information, first of all, i'm testing inserting a number with comma in a box and then converting to a number with dot to be displayed in another box. In the future i'wont dsplay numbers with comma, just with dot. So this is like a test if matlab is converting in the right way to let me proceed with maths.

[Stephen23]

What is the value of X1_pu ?

[Jucimar Carpe]

0.2 but want to have the possibility to enter 0,2 as well.

[Walter Roberson]

If X1_pu is coming out as double and scalar, then the implication is that Limits is the problem.

[Jucimar Carpe]

Yah, thats true.

But the questoin is: Is it possible to converto from comma to dot?

Or in the worst scenario, it it possible to create a pop window to inform the user that it must enter a number with dot?