Hanna Instruments HI 98402 Thermometer User Manual


 
89
CALIBRATION
In order to obtain accurate measurements, frequent calibration is
recommended.
For better results, calibrate at a temperature close to that of the
solution to be tested (no more than ±3°C apart).
The instrument can be calibrated at 1 or 2 points. Two-point calibra-
tion is always recommended for better accuracy.
Calibration points can be chosen among 1 ppm fluoride, 2 ppm , 10
ppm, 100 ppm and 1000 ppm.
PREPARATION
The HANNA calibration solutions at 1 ppm (HI 4010-11), 2 ppm
(HI 4010-12) and 10 ppm (HI 4010-10) are already mixed with
TISAB II solution, while for 100 ppm (HI 4010-02) and 1000
ppm (HI 4010-05) it is necessary to prepare the calibration
solutions by mixing with TISAB II (HI 4010-00), 50% and 50%.
Attach the fluoride and reference electrodes and the temperature
probe to their respective connectors on top of the meter.
Switch the meter on by pressing the ON/OFF button.
Note: For best results, it is recommended to prepare two beakers for
each calibration point: the first one to rinse the probes and the
second one to calibrate.
Note: It is recommended to use clean plastic beakers.
CALIBRATION PROCEDURE
Note: If the fluoride electrode is new, or it has not been used for a
few days, it must be soaked in a solution of HI 4010-10 (10
ppm fluoride solution + TISAB) for at least 3 hours prior to
measurement.
Rinse the electrodes with deionized water and dry them attentively
with a non-abrasive cloth.
Immerse the fluoride and the reference elec-
trode as well as the temperature probe at
least 1 cm (½”) in the calibration solution.
Make sure that the electrodes are not touch-
ing the bottom of the beaker. Immerse the
temperature probe close to the tip of the
other electrodes.
Press CAL. The display will show “CAL” and “BUF” together with
an intermittent “~” symbol. The upper display will show the
calibration point (10 ppm) with the temperature of the solution
shown on the lower LCD.
If the STD button is pressed, the instrument cycles through all the
available calibration values. Choose the point corresponding to the
first calibration solution.
When the CON symbol appears, it means that the calibration
solution has been recognized and the reading has stabilized. Press
CFM to confirm the first calibration point.
Note: If the calibration solution value mea-
sured by the meter is too far from
the ideal value, the “ “ symbol
starts blinking to indicate an error
in the calibration procedure.
Ensure that the calibration solution is fresh and the correct one
(in this case 10 ppm), and that the electrodes are in good
working condition. Repeat the procedure with fresh and/or new
solutions and electrodes.
After pressing CFM, the display shows the second calibration point.
It is always recommended to perform a two-point calibration.
However, to exit the calibration procedure at this point, press CAL.
Press STD to choose the point corre-
sponding to the second calibration
solution. The instrument cycles through
all the available calibration values,
skipping the standard used as the first
calibration point.