HEIDENHAIN iTNC 530 (60642x-04) ISO programming - Manual (Page 268)

268 Programming: Subprograms and Program Section Repeats
8.2
Subpr
ogr
ams
Calling a subprogram
 To call a subprogram, press the LBL CALL key
 Call subprogram /repeat : Enter the label number of
the subprogram you wish to call. If you want to use a
label name, press the LBL NAME soft key to switch
to text entry. If you want to enter the number of a
string parameter as target address: Press the QS soft
key; the TNC will then jump to the label name that is
specified in the string parameter defined
G98 L 0 is not permitted (Label 0 is only used to mark the
end of a subprogram).