horiba U-51, Инструкция по эксплуатации

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3 Basic Operation
58

Dissolved oxygen (DO) calibration
Note

You can select one calibration procedure (span calibration) or two calibration procedures (zero-
point calibration and span calibration). Carry out the two calibration procedures to ensure good
measurement precision throughout all measurement ranges.

It is necessary to prepare new solution before calibration of the Dissolved Oxygen (DO) sensor.

The calibration cup (included) cannot be used to manually calibrate the DO sensor. Use a
suitable bottle in which the DO sensor and the temperature sensor can be immersed.

Wait at least 20 minutes after turning the system power ON before calibrating the DO sensor.

Make the compensation setting before calibration since the setting is applied during calibration.

The DO sensor is affected by flow. When performing span calibration with saturated dissolved
oxygen water, move the cable slowly up and down (move the sensor probe at a rate of roughly 20
to 30 cm a second) or agitate the saturated dissolved oxygen water.
1.
Prepare the standard solution.

Add about 50 g of sodium sulfite to 1000 mL of water (either deionized water or tap
water) and stir the mixture to dissolve the sodium sulfite in it.

Pour 1 to 2 liters of water into a suitable flask (either deionized water or tap water).
Using an air pump, feed air into the water and aerate the solution until oxygen is
saturated.
2.
First, calibrate the zero point. Press the control unit’s CAL key to set the calibration
mode.
3.
Press the down (  ) key to move the cursor to "Manual Calibration", then press the
ENTER key.
4.
In the parameter selection screen, move the cursor to DO or DO%, then press the
ENTER key.
5.
Set the number of calibration procedures, then press the ENTER key.
The instructions below assume that two calibration points have been set.