You can modify variable ranges only in Crocodile Technology.
Each new variable used in a flowchart is added to a list displayed on the Start part. Look at the list by clicking on the Edit variable ranges button which appears when you drag the mouse over the part. You can select one of two maximum values for each variable used in a routine:
(Note that the minimum value of a variable in Crocodile Technology is always 0.)
The choice of maximum values corresponds to the 8-bit (byte) and 16-bit (word) storage available in microcontrollers.