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3.3 Dissolved Oxygen Calibration
1. Plug the Dissolved Oxygen sensor into the
Oxygen
socket.
2. Switch the meter on.
3. Select the Dissolved Oxygen readout mode to be used, as detailed in section 3.1.
4. Ensure that the Temperature readout has been calibrated. When a separate Temperature sensor
is connected, the
smart
CHEM
-D
will use it for Automatic Temperature Compensation in the
ppM Dissolved Oxygen modes. When the Temperature sensor is not connected, the
smart
CHEM
-D
will use the Temperature sensor built into the tip of the Dissolved Oxygen
sensor for Automatic Temperature Compensation in the ppM Dissolved Oxygen modes.
It is vital that the correct Temperature sensor is calibrated. See section 6.1 for a detailed
explanation.
5. Rinse the Dissolved Oxygen sensor (and Temperature sensor, if applicable) in distilled water
and blot dry.
3.3.1 Zero Calibration
1. Place the sensor(s) into an oxygen-free solution. This solution may be prepared by dissolving
2g of Sodium Sulphite in 100mL of distilled water. A 50g bottle of Sodium Sulphite powder
(part number 123302) is supplied with a new Dissolved Oxygen sensor for this purpose.
2. Allow the reading to stabilise at or near zero. This may take 2-3 minutes.
3. Select Oxygen Calibration. (
→
→
F1:Calibrate
→
→
F1:Oxygen
)
When the reading is below approximately 25 % Saturation, 2 ppM or 5% Gaseous, the
smart
CHEM
-D
will display the ZERO calibration screen…
0*1%S
25.0
O
C
Oxygen ZERO Cal.
Press Enter
4. Press
to calibrate. The Automatic Stability Function will now show a and highlight any
unstable readings…
0*1
%S
25.0
O
C
Oxygen ZERO Cal.
Waiting to Stabilise
When the Dissolved Oxygen and Temperature readings have both stabilised, the unit will
calibrate itself.
To calibrate immediately without waiting for complete stability, press
to disable the
Automatic Stability Function.
A “
∗
” will not be removed from the display after a Zero Calibration.
5. Remove the sensor(s) from the Zero solution, rinse well in distilled water and blot dry.
The
smart
CHEM
-D
will now prompt you to perform an AIR calibration.
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