35
Calibration
3.5
Dissolved Oxygen
ODO calibration requires the current “true” barometric pressure. Make sure that the barometer is reading accurately
prior to ODO calibration.
Calibrating in DO% or DO% local automatically calibrates the mg/L and ppm measurement. There is no reason to cali-
brate both parameters. For both ease of use and accuracy, we recommend that you calibrate DO% or DO% Local and
not mg/L.
ODO% and ODO% Local - Water
Saturated Air Calibration
1.
Place a small amount of clean water (5 mL) in the calibration cup or
a wet sponge into the calibration sleeve (for ODO/T and ODO/CT
probes).
2.
Make sure there are no water droplets on the ODO sensor cap or
temperature sensor.
3.
Attach the probe guard and carefully slide into the calibration cup.
Make sure a seal is not created around the probe. Atmospheric
venting is required for accurate calibration.
4.
Turn the instrument on and wait approximately 5 to 15 minutes for
the air in the storage container to be completely saturated with
water.
5.
Push the
Cal
key, then select
ODO.
Select
DO%
.
6.
Observe the actual measurement readings for stability (white line
on graph shows no significant change for 40 seconds), then select
Accept Calibration
(
Figure 51
). “Calibration successful!” will be
displayed in the message area.
NOTE:
If you see a calibration error message, verify the barometer
reading and inspect the sensor cap. Clean and/or replace
the sensor cap as needed.
Figure 51
Calibrate ODO %
