.nf 
/TUNE xOffsetT yOffsetT
or
/TUNE NO                  ! no tune subscan

Tune subscan at the specified offsets, before any other subscans.

Real      :: xOffsetT          ! x-offset for tune subscan
Real      :: yOffsetT          ! y-offset for tune subscan

NOTE: with the usage /TUNE xOffsetT yOffsetT, both parameters are required,
but you can replace either parameter with * to leave it unchanged.

.fi
