how does the variable declaration for _VAC_KOMP look like
I checked the following nc code and it works properly
def nck real _VAC_KOMP _VAC_KOMP=100 X=((_VAC_KOMP*2)-0.5)
Keep in mind that the field size definition is zero based. So accessing _VAC_KOMP on field  will not work. Therefore the highest possible value is 199 when its defined with a field size 200.
I did tried to define the variable in Machine Configurator as a global variable.
Now I put in the definition in the ini-file.
Thanks for a quick answer.
it´s not a problem if its defined in the Machine Configurator and if its global or not. It´s a question of the size definition of this array. It doesn´t matter if its defined in MC or in the ini file. Both places are valid and work similar.