Hach 2100N Basic User Manual page 19

1. Turn off the instrument.
2. Push and hold CAL.
3. Turn on the instrument.
The CAL? light flashes. The instrument starts in Calibration mode.
4. Calibrate the instrument before use.
Flashing 9s
When manual ranging is selected, the display will flash all 9s when the
sample being measured is greater than the selected range.
When automatic ranging is selected, the display will flash 9s when the
sample is greater than the maximum range of the instrument. The
display will also flash 9s if Ratio is off and the measurement is greater
than 40 NTUs (268 nephelos or 9.8 EBCs). Turn Ratio on.
Flashing 0s
When manual ranging is selected, the display will flash all 0s when the
sample measured is less than the selected range.
When automatic ranging is selected, the display will flash all 0s when the
measurement is less than the range of the instrument or a negative
value. Calibrate the instrument.
English 19