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5.2
Resolution Selection
The resolution unit can be selected in parameter setting P3.2: 0.01 or 0.1mg/L (ppm). After
setting, the meter will display resolution of 0.1 or 1 in according to %.
5.3 Temperature Unit Selection
The temperature unit can be selected in parameter setting P4.1: ˚C or ˚F
5.4 Air Pressure Compensation
The instrument has automatic air pressure compensation function. The air pressure has
been calibrated before the product left the factory. So in general users do not have to
calibrate air pressure any more. If necessary, calibrate it according to standard value
measured by aneroid barometer. Refer to parameter setting P3.4 for the procedure of
aneroid barometer calibration.
5.5 Salinity Compensation
The instrument has manual salinity compensation. It is set in the parameter P3.3 (0 to 45
ppt). To obtain accurate readings in mg/L and ppm, it is necessary to know the salinity of the
test sample and input salinity value into the instrument. As the salinity of the solution
increases, the level of DO decreases. Generally, salinity of freshwater is 0 to 0.5ppt, salinity
of seawater is 35ppt.
6
Calibration
6.1
Saturated Oxygen Calibration
(A)
This procedure requires the use of a calibration sleeve to allow the probe to be calibrated
in a humidity-saturated atmosphere.
(B)
Check if the sponge in the calibration sleeve is damp. Attach the calibration sleeve to
the probe. Tighten the locking cap. Be careful not to have water droplets on the head of
the sensor cap. Wait for 5 to 10 minutes after turning on the instrument in order to
saturate the air in the calibration sleeve with water vapor. In addition, wait for the
temperature to completely stablize.
(C)
Long press to enter the calibration mode, and
CAL
is flashing in the upper right
corner. Wait for the stable to appear and stay on, press
to finish calibration,
once
100%
starts flashing, the saturated oxygen calibration is completed.
6.2
Zero -Oxygen Calibration
Zero-Oxygen calibration is only performed when a probe or sensor cap is replaced, the
probe has not been used for a long time, or users have a requirement for high accuracy in
low DO range (0 to 2.0 ppm). Zero-Oxygen calibration is done at the factory before shipment,
so it is not necessary to perform it during initial use. Zero-oxygen calibration should follow
