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MA300TS-0210
If an error message appears during the calibration, refer to the “Error Messages” section on page 19 of this
manual, and the “Error Messages” section in the PACK MASTER Operation Manual.
(3) Zero calibration
To measure low concentrations accurately, or if the value when measuring low concentrations seems abnormal (negative
display or a higher value than usual), perform zero calibration following the procedure below.
Step 1. Prepare the zero standard liquid (zero water).
Dissolve 5 g of sodium sulfite in a container such as a beaker, and add water so that the total volume is 100 mL.
(When preparing enough liquid to change the entire amount, adjust with the same ratio.)
Stir until the sodium sulfite completely dissolves. The sodium sulfite will dissolve more easily if added to the water
while stirring. Avoid making air bubbles when stirring.
Step 2. Directly place the oxygen sensor in the container holding the zero water. (The housing is not used.)
Wait approx. ten minutes for the indicated value to drop to about 0.00 mg/L.
Make sure that there are no air bubbles on the tip of the sensor.
Step 3. When the DO MEASURE screen is displayed, press .
The MENU screen opens, and “CAL” is selected (flashes).
Step 4. Press .
The DO CAL screen opens.
Step 5. When the indicated value stabilizes, hold down for 1
second or longer.
The stability is decided, and after approx. 10 seconds “CAL complete”
appears to indicate that the calibration is complete.
The DO MEASURE screen opens when the automatic calibration is completed. The calibration value is saved
even if the PACK MASTER power is turned OFF, the batteries are removed, or the AC adapter is disconnected.
Step 6. Wash the oxygen sensor with tap water filled in a container such as a beaker.
Refer to section “6. Maintenance (1) Cleaning after the measurement” on page 16 of this manual.
Prepare the zero water at the time of use, not in advance.
Perform zero calibration with a container such as a beaker. Do not use the housing. If the zero
water passes through the housing, the residual amount of zero water left in the housing or tubing
after zero calibration could affect the ensuing sample measurement values.
When the zero calibration is completed, always clean the oxygen sensor with tap water. If a
measurement is performed without cleaning the sensor, the residual zero water could affect the
measurement values.
Always clean the oxygen sensor with tap water filled in a container such as a beaker. If cleaned
with tap water directly from the faucet, the pressure of the water could break the membrane on the
sensor surface.
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