s7 simaticmanagr v5.5 program

How to choose two values which one correct in result basis..example encoder monidering each station ..some time mw2 less than 360 degree correct valve...but greater than 360 ,add calculation program after result enter same mw2,..if possible? Mw 0 actual value mw 0,+330 =mw2, station value in 2, but greater than 360 degree mw2, -360= mw4 , mw 4 how to enter in mw2 ,because mw2 HMI DISPLAY IN STATION NO2

You may want to rewrite that, because I did not get any of that...