GENERAL DESCRIPTIONS
This Digital Dissolved Oxygen Meter is supplied with a polarographic type probe with an incorporated Temp. sensor which serves for precise Dissolved Oxygen ( DO ) and Temp. measurement. Applications for Aquarium, Medical research, Agriculture, Fish hatcheries, Laboratory, Water conditioning, Mining industry, Schools & Colleges, Quality control…
1 Calibration
Before measurement, need to make following calibration procedures: 1)Disconnect the ” OXYGEN PROBE plug ” ( 3-12, Fig. 1 ) from the main instrument ” Input socket ” ( 3-6, Fig. 1 ). 2)Power on the instrument by select the ” On/Off Switch ” ( 3-2, Fig. 1 ) to the ” On ” position. Slide the ” DO / CAL Switch ” ( 3-3, Fig. 1 ) to the ” CAL ” position. Adjust the ” ZERO Adj. VR ” ( 3-4, Fig. 1 ) until the display show zero value. 3)Power off, connect the ” OXYGEN PROBE plug ” ( 3-12, Fig. 1 ) to the main instrument ” Input Socket ” ( 3-6, Fig. 1 ), then power on. Wait 5 minutes at least until the display reading values become stable & no fluctuation. Adjust the ” CAL Adj. VR ” ( 3-5, Fig. 1 ) until the display reading show the values exact same as 20.9 (As the oxygen in air is 20.9 % typically, so use the environment air 02 value for quick & precise calibration)
Calibration consideration : Please make calibration procedures under wide and ventilating environment for best effect.
2 Dissolved Oxygen ( DO ) measurement 1)After the meter be calibrated ( above procedure 4-1 ), don’t adjust the ” CAL Adj. VR ” & ” ZERO Adj. VR ” again until next calibration procedures be done. 2)Slide the ” DO / CAL Switch ” ( 3-3, Fig. 1 ) to the ” DO ” position. a. Immersed the probe to a depth at least 10 cm of the measured liquid in order for the probe to be influenced by the temp. & automatic temperature compensation to take place b. As for the thermal equilibrium to occur between the probe & the measurement sample must be allowed to pass, which usually amounts to a few minutes if the temp. difference between the two is only several C degrees. 4)a. In order to measure the dissolved oxygen content in any given liquid, it is sufficient to immerse the tip of the probe in the solution, making sure that velocity of the liquid coming into contact with the probe is at least 0.2 – 0.3 m/s or shake the probe. b. During laboratory measurements, the use of a magnetic agitator to ensure a certain velocity in the fluid is recommended. In this way, errors due to the diffusion of the oxygen present in the air in the solution are reduce to a minimum. 5)Rinsed the probe accurately with normal tap water after each series of measurement.