EUTECH INSTRUMENTS CD 650, Instruction Manual

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2. DO Calibration in % Saturation Mode (with
ATC)
2.1 About DO(%) and DO (mg/L) Calibration
The calibration of % Saturation of DO will linearly affect the measurement
for DO in mg/L. The amount of oxygen dissolved in water will depend on its
temperature, atmospheric pressure and its salinity. It is therefore very
important that the temperature is calibrated if necessary prior to the DO
calibration.
Hence calibration in % Saturation of DO should be carried out first.
This is
described in the following section.
The 600 series meters can be calibrated quickly and easily in air. In %
Saturation, the meter is able to perform either a one point calibration or a 2
point calibration. For one point calibration, it is recommended that you
perform a 100% Saturation calibration in saturated air. If you opt for 2 point
calibration, you can calibrate for 100% Saturation in saturated air and 0%
Saturation using a zero oxygen solution.
The meters are capable of measuring barometric pressure with its built-in
pressure sensor. In the event, the pressure reading is inaccurate, you can
calibrate the value from the setup menu.
2.2 To calibrate 100% saturation
1. Switch the meter on and make sure the meter is in % saturation mode.
2. Hold the probe in the air gently with the sensor facing down and press
CAL (F2) to start calibration.
3. The meter shows the ‘Dissolved O
2
Calibration-Rinse Electrode’ screen
for a few seconds to prompt user to rinse electrode with de-ionized
water before calibration.
Note: If the meter is password protected, you will be prompted to enter a
password.