HEIDENHAIN TNC 320 User Manual page 250

Configuring the datum table
If you do not wish to define a datum for an active axis, press the DEL
key. Then the TNC clears the numerical value from the corresponding
input field.
Exiting a datum table
Select a different type of file in file management and choose the
desired file.
After you have changed a value in a datum table, you must
save the change with the ENT key. Otherwise the change
may not be included during program run.
Status displays
In the additional status display, the TNC shows the values of the active
datum shift.
250 Cycles: Coordinate Transformations