Hanna Instruments HI 98180 Instruction Manual page 41

Note: If enabled "CAL DUE" warning will be displayed, the set number of
days after calibration is over passed.
First point mode
Focus on the First Point item.
Press the displayed functional key in order to change the option.
First point mode refers to the behaviour of the instrument regarding "One
point calibration".
If Offset is set, after one point calibration the instrument evaluate the offset
and keep unchanged the slopes.
Custom Buffers
Focus on the Custom Buffers item.
Press Modify.
Press Delete to delete focused buffer.
Press Add to add a new buffer to the list (max 5).
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