EUTECH INSTRUMENTS CD 650, Instruction Manual

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2. DO Calibration in mg/L mode or ppm
Concentration mode
The amount of oxygen dissolved in a liquid will depend on its temperature,
atmospheric pressure and salinity. It is therefore very important to set
temperature and salinity correctly before attempting to do a calibration. The
meter is 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.
1. Switch the meter on. Make sure the meter is in concentration
measurement mode.
2. Rinse the probe well with de-ionized rinse water. For best accuracy,
blot the end of the probe to dry it. Do not touch the membrane. Dip the
probe into a solution with a known DO value.
3. Press CAL (F2) to go to calibration mode.
4. The meter shows ‘Dissolved O
2
Calibration-Rinse Electrode’ screen for
a few seconds to prompt user to rinse electrode with de-ionized water
before calibration.
Figure 58 : Concentration Calibration Screens
5. The meter then shows the concentration calibration screen.
6. The upper display of the calibration screen will show the current value
of the measurement and the secondary display will show the value to
Note: If the meter is password protected, you will be prompted to enter a
password.