Hitachi ZA3000 Series Instruction Manual page 247

Fig. 3-13 Change of Sample Table (2)
b. When the number of samples in sample table equals the
entered [No. of UNK]:
Content of the sample table will not be changed.
c. When the entered [No. of UNK] is smaller than the
number of samples in sample table:
Example of execution;
Click [Change] button with 10 set for number of samples
in sample table and 5 set for [No. of UNK].
Fig. 3-14 Change of Sample Table (3)
The number of entered [No. of UNK] from the head
(No.1) of the sample table is left and the UNK sample
after that is deleted.
Fig. 3-15 Change of Sample Table (4)
3 - 23
3.1.7