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It is not necessary to calibrate in both % and mg/L or ppm.
Calibrating in % will simultaneously calibrate mg/L and ppm
and vice versa. YSI recommends calibrating dissolved oxygen
in % for both ease and accuracy.
i
ONE TOUCH CALIBRATION
Perform this calibration procedure when One Touch Cal is enabled in
the System Setup menu.
If using a field cable, install the sensor guard onto the probe. Moisten
the sponge in the grey calibration/storage sleeve with a small amount
of water and install it over the sensor guard. The sleeve should be
moist, but should not have excess water that could cause water
droplets to get on the membrane. The storage sleeve ensures venting
to the atmosphere.
If using the ProBOD sensor/cable assembly, place the probe in 300
ml BOD bottle with a small amount of water (1/8 inch or 0.3 cm). The
dissolved oxygen and temperature sensors should not be immersed
in water.
If the calibration/storage sleeve is not available, substitute with a
chamber of 100% relative humidity, vented to the atmosphere (not
completely sealed).
Power the instrument on and wait approximately 5 to 15 minutes for
the storage chamber to become completely saturated and to allow the
sensor to stabilize if using a Polarographic sensor. If using a Galvanic
sensor, wait approximately 5 to 10 minutes for the chamber to become
completely saturated. Auto Shutoff time should be disabled or set to
at least 20 minutes, see System Setup menu for more information on
adjusting the Auto Shutoff.
Ensure the barometer reading is accurate. If necessary, perform a
barometer calibration.
Press and hold the Calibrate
key for 3 seconds. The Pro20/Pro20i
will indicate
Calibrating %DO
on the display and automatically
calibrate the sensor to the barometer and salinity correction values.
This may take up to 2 minutes depending on the age of the sensor
and membrane. You may press the Cal key at this time to cancel the
calibration.
