TheMemberFormerlyKnownAsAWOL:
#define umrechnungsfaktor 0.1;Be very, very careful when putting semicolons at the the end of preprocessor macros
david_2018:
Did you forget something here?#define Schwellenwert_St2
That's why you shouldn't be using macros to define constants. The preprocessor is a stupid text processor, it just copies and pastes text, it doesn't care about type safety or syntax rules.
Use the compiler to handle your constants, that'll avoid hard to spot bugs an cryptic error messages later on.
constexpr float umrechnungsfaktor = 0.1;
(Idem for all other #defines in your code, every one of them can - and should - be replaced by a constant.)
Pieter