Hach 2100AN Instrument Manual page 40

SECTION 3,
continued
5.
Press .
ENTER
The instrument display
counts down from to
60 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
water 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
"ignored" rather than reading
the dilution water. Refer to
Section 3.3.1 on page 44.
6.
The instrument
automatically increments
to the next standard,
,
displays the expected
NTU value (e.g.,
20.00 NTU), and the
standard number 01 is
shown in the mode
display. Remove the
sample cell from the cell
holder.
7.
Fill a clean sample cell
to the line with well-
mixed, 20-NTU Formazin
standard. Wipe the sample
cell clean, and apply a thin
film of silicone oil on its
surface. Place it into the
cell holder, and close the
cell cover.
40
8.
Press .
ENTER
The display counts down
from to , and takes a
60 0
measurement. The
instrument applies a
correction factor to
compensate for turbidity
of the dilution water. The
instrument automatically
increments to the next
standard, the display
shows 200.0 NTU, and the
standard number is
02
displayed. Remove the
sample cell from the
instrument.