horiba U-51, Инструкция по эксплуатации

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3 Basic Operation
50

Conductivity (COND) calibration
Note

To support a wide range of sample concentrations, electrical conductivity is divided into three
measurement ranges: 0.0 mS/m to 99.9 mS/m, 0.090 S/m to 0.999 S/m, and 0.9 S/m to 9.99 S/m.

When manually calibrating conductivity, you can select two calibration points (one zero-point
calibration point and a span calibration point for one of the three measurement ranges) or four
calibration points (one zero-point calibration point and span calibration points for all three
measurement ranges). Carry out the four calibration points to ensure good measurement
precision throughout all measurement ranges.

Make the compensation setting before calibration since this setting is applied during calibration.
(Refer to “ 6.5.3 Temperature coefficient ” (page 111)).
1. Prepare the standard solution. Dry Potassium chloride (KCl) powder (high-grade
commercially available) at 105

C for two hours, and leave it to cool in a desiccator.
2.
Consult the following table and weigh potassium chloride (KCl), then prepare three
standard potassium chloride (KCl) solutions following the procedure below.
3. Dissolve the weighed Potassium Chloride (KCl) in deionized water.
4. Put the dissolved Potassium Chloride (KCl) into a 1 L measuring flask, and fill to
the 1 L mark with deionized water.
5.
Calibrate the zero point. Wash the sensor probe 2 or 3 times in deionized water to
remove any dirt, then remove all moisture from the sensor probe (it will be
calibrated in air).
6.
Press the control unit’s CAL key to set the calibration mode.
7.
Press the down (  ) key to move the cursor to "Manual Calibration", then press the
ENTER key.
Potassium
chloride (KCl)
standard
solution
Conductivity
(COND) value
Potassium chloride (KCl)
mass (g) at solution
temperature of 25°C
Calibration range
0.005 mol/L
71.8 mS/m
(0.718 mS/cm)
0.373
0.0 mS/m to 99.9 mS/m
(0.00 mS/cm to 0.999 mS/cm)
0.050 mol/L
0.667 S/m
(6.67 mS/cm)
3.73
0.090 S/m to 0.999 S/m
(1.00 mS/cm to 9.99 mS/cm)
0.500 mol/L
5.87 S/m
(58.7 mS/cm)
37.2
0.9 S/m to 9.99 S/m
(10.0 mS/cm to 99.9 mS/cm)