Operation; Polarisation; Measurement - Hach sensION+ DO6 Manuel Utilisateur

6. Operation

6.1. Polarisation

The sensor must be connected and polarized before calibration. The measuring instrument polarizes the
sensor whenever it is connected, even if it is switched off.
Required polarisation
The sensor must be polarised 6 hours before use if:
• it is not connected to the measuring instrument
• the batteries have been inserted for the first time, they are running low or they need changing
The sensor must be polarised for 10 approximately minutes if the sensor is disconnected from the measuring
instrument for less than 5 minutes.

6.2. Measurement

1. Press to turn on the instrument.
2. Remove the sensor protector.
3. Clean the sensor with deionized water.
4. Stir the sensor uniformly in the sample, holding it by the top.
Important notes: the instrument must be calibrated before taking the first reading.
The DO sensor consumes oxygen in the measured solution; hence, the liquid in contact with the membrane
needs to be renewed for a correct measurement. Otherwise, the reading will gradually drop. Gently stir the
liquid to be measured using the sensor. The minimum flow must be 0.3 mL/s.
Before measuring, the sensor must be fully polarised.
Salt content affects oxygen measurement when the result is expressed in mg/L and it must be adjusted
manually. To do this, measure the conductivity of the sample, determine the salt content (see table on pg. 9) and
manually enter it in the instrument.
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