Hach Lange 2100AN, Instrument Manual

Page: 41 / 108

SECTION 3,
continued
41
9.
Fill a clean sample cell
to the line with well-
mixed, 200-NTU
Formazin standard. Wipe
the cell clean and apply a
thin film of silicone oil to
the surface. Place it into
the cell holder, and close
the cell cover. Press
ENTER
.
The instrument display
counts down from 60 to 0,
and then makes a
measurement. The
instrument automatically
increments to the next
standard, the display
shows 1000 NTU, and the
standard number 03 is
displayed. Remove the
sample cell from the
instrument.
10.
Fill a clean sample
cell to the line with well-
mixed, 1000-NTU
Formazin standard. Wipe
the cell clean and apply a
thin film of silicone oil to
the surface. Place it in the
cell holder and close the
cell cover. Press
ENTER
.
The instrument display
counts down from 60 to 0,
and then takes a
measurement. The display
automatically increments
to the next standard, the
display shows 4000 NTU,
and the standard number
04 is displayed. Remove
the sample cell from the
instrument.
11.
Fill a clean sample
cell to the line with well-
mixed, 4000-NTU
Formazin standard. Wipe
the cell clean and apply a
thin film of silicone oil to
the surface. Place it in the
cell holder and close the
cell cover. Press
ENTER
.
The instrument display
counts down from 60 to 0,
and then takes a
measurement. The display
automatically increments
to the next standard, the
display shows 7500 NTU
and the standard number
05 is displayed. Remove
the sample cell from the
instrument.
12.
Handling the
7500-NTU Formazin
ampule by the top, mix by
gently inverting several
times. Wipe the ampule
clean and apply a thin film
of silicone oil to the
surface. Place it in the cell
holder and close the cell
cover. Ensure that the
ampule orientation mark
is aligned with the sample
cell holder reference
mark. Press
ENTER
.
The instrument display
counts down from 60 to 0,
and then takes a measure-
ment. The displayed
standard number will
increment back to
00
and
the previously measured
value of the dilution water
is displayed.
13.
Press
CAL/Zero
.
The instrument makes
calculations based on the
new calibration data,
stores the new calibration
and returns the instrument
to the measurement mode.
Note: If power is lost during
calibration, new calibration
data is lost, and the old
calibration remains in effect.
To exit calibration without
saving new values, press
UNITS/Exit
.
Note: If
ERR01
or
ERR02
appears in the display, an error
occurred during calibration (refer to Table 5 on page 95). Clear
the error message and proceed with measurements by
pressing
ENTER
. However, Cal? annunciator will be on,
indicating a questionable calibration. The
Cal?
annunciator is
turned off only by recalibration, which removes erroneous data.
Prepare new standards, and recalibrate the instrument. Make
sure the Formazin standards are fresh and well mixed. Also
check to ensure dilution water is < 0.5 NTU.