8
8-1 Calibration
This controller is Two-Point Calibration type and supports Air calibration and Solution calibration.
Air calibration makes Zero calibration set automatically.
Solution calibration is recommended to use 0.2mol Na
2
SO
3
(Na
2
SO
3
12g + distilled water 500ml) as Zero
standard solution. Refer to the below table for saturation dissolved oxygen according to temperature. (Under
the condition of 1atm and salinity 0ppt)
Temperature(℃) Dissolved oxygen(mg/L) Temperature(℃) Dissolved oxygen(mg/L)
0 14.62 25 8.26
5
12.77 30
7.56
10 11.29 35 6.59
15 10.08 40 6.41
20 9.09 45 5.93
8-2 Cautions for calibration
In calibration mode, do not be changed to Measuring Mode even after several minutes.
To exit the Calibration Mode, should stop calibration by pressing the CAL Key or complete calibration by
pressing the ENTER Key.
During calibration, if press CAL key to exit Calibration Mode or the Calibration Mode is exited in an
unusual manner, such as power off, Calibration Values are not stored.
Clean the electrodes with clean or distilled water before submerging it.
The dissolved oxygen is much inuenced by the rate of liquid ow. Calibrate the rate with the same ow
rate obtained at the time of measurement. The reliability of the measure value is reduced, if the ow rate
at the time of calibration is different from that at the time of measurement.
Calibrate in the manner that the range to be measured falls within the Zero and Span range; otherwise, its
accuracy drops.
(Ex. Meas: 8ppm
Zero: 0ppm, Span: 10ppm)
Solution calibration will be more accurate than air calibration.
It is recommended that the Span calibration should be at least in excess of 5ppm.
There can be a considerable difference between analysis by an instrument and analysis by a reagent.
Analysis by a reagent is advised to adopt to have precise measurements.
8
Calibration
7-2 Rear
①
Relay High : HIGH Alarm Output Terminal
②
Relay Low : LOW Alarm Output Terminal
③
Power : Power Supply Terminal
④
Sensor : Electrode Connection Terminal
⑤
Process : Analog Output Terminal for 4~20mA
of 0 ~ 20ppm
⑥
Temp : Analog Output Terminal for 4~20mA
of -10 ~ 100℃ (Option)
Warning
•Do not handle calibration powder or solution used for product calibration by children or the elderly & the
infirm, since it may be harmful to the human body.
Be sure to follow the doctor's prescription when drinking it.
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