17
•
Turn the instrument on by pressing ON/OFF and select the
appropriate range (e.g. 1999 mg/L).
•
Tap the probe repeatedly on the bottom of the beaker and stir it
to ensure that no air bubbles are trapped inside the sleeve.
•
If the temperature of the probe is close to that of the solution, the
display will stabilize quickly and provide you with temperature
compensated TDS measurements. However, allow a few minutes if
there is a temperature difference of 5°C (9°F) or more for the ATC
circuitry to compensate completely.
•
When the reading stabilizes, turn the calibration trimmer until
the display reads the proper TDS value @25°C.
For example, when calibrating with HI 7032 turn the trimmer to
read 1382 mg/L @25°C.
Note:
It is also possible to standardize the calibration to have
readings compensated to 20°C (68°F) rather than 25°C
(77°F). Simply adjust the trimmer to the calibration buffer
reading at 20°C (68°F). For example, for HI 7032 this value
is 1251 mg/L and can be found on the TDS vs. temperature
chart on page 23.
The calibration is now complete and the instrument is ready for use.
All subsequent measurements will now be compensated to 25°C
(77°F).
If the instrument cannot be calibrated, refer to the Probe Mainte-
nance section (page 30).
You can calibrate the instrument using any other Hanna calibration
solution in exactly the same way. For example with HI 7038 turn the
trimmer to obtain 6.44 g/L @25°C.
ON/OFF
1999mg/l
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