Making Measurements - VOLTCRAFT DO-500 Bedienungsanleitung

4. Leave the sensor in the air. Press and hold the
the calibration process. The calibration "CAL" symbol appears in the LCD display (6) and of
the saturation value of 101.7 % starts to flash.
5. The display stops flashing and first displays "SA" and then "End". The calibration process is
complete. The device automatically reverts to "Measuring" operating mode.
The operating mode with the symbol "O2" is only intended for calibration. The oxygen
content of the air cannot be measured.
Optional zero oxygen calibration
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This setting improves the measurement accuracy when measuring very low or very high oxygen
content.
1. Immerse the sensor in an oxygen-free calibration solution, such as 5 % sodium sulphite.
2. Leave the measuring sensor in the solution. Wait until the value has stabilised, before select-
ing calibration.
Displaying a stable zero value in a zero solution can take a few minutes depending on
past use of the sensor prior to calibration.
If the value displayed without the sensor connected is not "0", first calibrate in the air
without the sensor, to set to a reading of 0 %.
f) Making measurements
1. Remove the sensor protective cap (12).
2. Rinse the measuring sensor prior to measurement with distilled water and wipe it dry.
3. Press the
4. Wait approximately 10 to 30 minutes, until the sensor has polarised. The measured value
displayed should be approximately 101.7 % saturation. This means that the sensor has
completely polarised.
5. Select the desired operating mode with the corresponding unit, by pressing the
ton (10) until the desired operating mode/unit is shown on the display.
6. Immerse the tip of the measuring sensor approx. 2 - 3 cm into the liquid to be measured.
Move the tip of the measuring sensor around gently in the liquid, back and forth, to remove
air bubbles from the membrane surface and to stabilise the measured value displayed. It
takes some time until the measured value has stabilised.
7. If the measured value is outside the measurement range, the "----" error message appears
in the LCD display (6).
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button (4) to switch on the meter.
button (4) for approx. 3 seconds, to start
but-