Conversion Rules

hi

I am new in Abap and I have a little problem: I set an input field on my screen type string. When I process the text in it in PAI, i see the text has been converted to lower case. In debug I see that when the PAI start the text has already been converted in upper case, so I realize that a default conversion rule has been applied. Is there a way to tell that for a field there is no need to apply a conversion rule? Or a conversion that do not change lower to upper?

I see that for parameter there is syntax "LOWER" to let unchanged the case of the parameter, but I can't believe there is no way to do it with a simple input field.

Thanks

Gabriele