Hach-Lange 2100P iso - Portable Turbidimeter Instrument - Manual (Page 22)

Page 22
Calibration
4650098 operation.fm
Section 2, continued
• To review a calibration, press
CAL
and then × to view the calibration standard
values. As long as
READ
is never pressed and
CAL
is not flashing, the calibration
will not be updated. Press
CAL
again to return to the measurement mode.
Note: For accuracy, use the same sample cell or four matched sample cells for all measurements during
calibration. Always insert the cell so the orientation mark placed on the cell during the matching
procedure is correctly aligned.
1. Rinse a clean sample cell several times with dilution water. Fill the cell to the
line (about 15 mL) with dilution water or use StablCal <0.1 FNU standard.
Note: The same dilution water used for preparing the standards must be used in this step.
2. Insert the sample cell in the cell compartment by aligning the orientation mark
on the cell with the mark on the front of the cell compartment. Close the lid.
Press
I/O
.
3. Choose signal average mode option (on or off) before pressing
CAL
. The
SIGNAL
AVERAGE
key is not functional in calibration mode.
4. Press
CAL
. The
CAL
and S0 icons will appear (the 0 will flash). The 4-digit display
will show the value of the S0 standard for the previous calibration. If the blank
value was forced to 0.0, the display will be blank. Press the right key to get a
numerical display.
5. Press READ. The meter will count from 60 to 0, (67 to 0 if signal average is on),
read the blank, and use it to calculate a correction factor for the 20 FNU standard
measurement. If the dilution water is >0.5 FNU, E1 will appear when the
calibration is calculated (See Preparing Dilution Water on page 21 for more
dilution water information). The display will automatically increment to the next
standard.
6. Remove the sample cell from the cell compartment.
The turbidity of the dilution water can be “forced” to zero by pressing the Ö key
rather than reading the dilution water. The display will show “S0 FNU”. Press
the × key to continue with the next standard.