Calibrating The 2100N (With Formazin Standard) - Hach 2100N Instruction Manual

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SECTION 3,
continued

3.2.4 Calibrating the 2100N (with Formazin standard)

1.
Fill a clean sample cell
to the line (approx. 30 mL)
with dilution water. Wipe the
cell clean and apply a thin
film of silicone oil (refer to
Section 2.6.1 on page 23).
Note: For best accuracy use
the matched sample cells for all
measurements during
calibration (refer to
Section 2.6.3.2 Matching
Sample Cells). An alternative
may be to use the same cell for
all standards.
Note: A portion of the same
dilution water used for
preparing standards must be
used in this step.
Note: To exit the calibration
procedure at any time without
changing any stored value,
press the UNITS/EXIT key.
Note: If using StablCal
stabilized formazin, use
the <0.1 standard.
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2.
Make sure the filter is in
place. Insert the sample cell
into the cell holder, and
close the cell cover.
Hach Company recommends only the use of
formazin or StablCal™ stabilized formazin
turbidity standards for the calibration of Hach
turbidimeters. Hach Company can not guarantee
the performance of the turbidimeter if calibrated
with co-polymer styrenedivinylbenzene beads or
other suspensions.
3.
Press the key.
CAL
The S0 annunciator lights.
The NTU value of the
dilution water used in the
previous calibration
is displayed.
Note: Ratio on and Ratio off
calibration data are measured
and recorded simultaneously.
Note: Calibration for EBC and
NEPH units of measure is
set automatically.
Note: Upon entering the
Calibration Mode, Automatic
Range, Signal Averaging On
and NTU units are
automatically selected. Upon
completion of calibration, all
operational modes are restored
to precalibration settings.
39
4.
Press the key.
ENTER
The instrument display
counts down from
60 to 0, and then makes a
measurement. This result is
stored and used to calculate
a correction factor for
measurement of all
NTU standards.
Note: If reading of dilution is
>0.5 NTU, an E1 error
message is displayed at the end
of step 11.
Note: The turbidity of the
dilution water can be "forced" to
zero rather than reading the
dilution water. Refer to Section
3.3.1 on page 44.