IM 50.560CA UA (B/4-03)
47
DEPOLOX
®
3
PLUS
RESIDUAL ANALYZER
3.2.4
Fluoride Calibration
NOTE: Fluoride measurement is optional.
WARNING: DO NOT CONTINUE TO USE BUFFER SOLUTIONS
AFTER USE-BY DATE. BUFFER SOLUTIONS WHICH HAVE
BEEN OPENED CAN ONLY BE KEPT FOR A LIMITED PERIOD.
READ THE LABEL ON THE BOTTLE.
NOTE: Sample water and buffer solution should have the same tem-
perature.
In case sample water temperature deviates from the reference temperature
of 77° F (25° C), calibrate the resp. value shown in the temperature table
(see label on buffer solution).
There are two methods for fluoride calibration. The first adjusts the zero
and the span settings for the fluoride range. The second calibration is an
“offset,” in which the fluoride sensor is exposed to a known fluoride
concentration solution and the displayed value is adjusted, up or down, to
match the known value. This calibration can also be performed on the
process water with the sensor in the flow cell. Verify that the fluoride
concentration of the process water has been accurately determined.
NOTE: The offset calibration is typically all that is recommended to
calibrate fluoride when first starting the unit or replacing the sensor.
The Depolox 3
plus
zero and span values are factory set in order to
properly work with the sensor. Complete the zero and span calibra-
tions, if there is a problem, only after completing the offset calibra-
tion.
•
Fluoride OFFSET Calibration
a. With sensor in flow block, test sample Fluoride residual.
b. Press the
F
key until the “CALIBRATION” menu is displayed.
Press the
▼
key until the “Fluoride offset” menu is found.
c. Press the
E
key.
d. Press
▼
or
▲
keys until the offset value is the difference of the
displayed fluoride value compared to the manually measured fluo-
ride solution value. Store this value using the
E
key. (Example:
The flow is measured at 0.20 mg/l fluoride solution. The basic
display reads 0.28 mg/l fluoride. The offset value will be ad-
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