XS Instruments 7 Vio User Manual

26
Rev. 1.0 30.01.2020
EN
the reference temperature. Therefore, the effect of temperature on the sample is corrected.
• On the other hand, when measuring pH, the pH value at the displayed temperature is shown on
the display. Here the temperature compensation involves the adaptation of the Slope and the
electrode offset to the measured temperature.
P3.3 Reference Temperature
Conductivity measurement strongly depends on temperature.
If the temperature of a sample increases, its viscosity decreases and this leads to an increase in the mobility
of the ions and the measured conductivity, although the concentration remains constant.
For each conductivity measurement, the temperature to which it refers must be specified, otherwise it is a
result without value. Generally, temperature refers to 25 °C or, more rarely, 20 °C.
This device measures conductivity at real temperature (ATC or MTC) and then converts it to the reference
temperature using the correction factor chosen in program P3.4.
• Access this setup menu to set the temperature to which you want to refer the Conductivity
measurement.
• The device can report conductivity from 15 to 30°C. By default, it is 25°C which is correct for most of
the analyses.
P3.4 Temperature compensation Factor
It is important to know the temperature dependence (% change in Conductivity per °C) of the sample being
measured.
• Access this menu to change the temperature compensation factor.
• By default, 1.91% / °C is set which is suitable for most of the analyses.
Press the key , the value flashes and as indicated by the icon use the directional keys
to enter the new coefficient. Confirm with key .
Compensation coefficients for special solutions and for groups of substances are shown in the following
table:
Compensation coefficients for calibration standards at different temperatures for T
ref
25 ° C are
shown in the following table:
°C
0.001 mol/L KCl (147µS)
0.01 mol/L KCl (1413 µS)
0.1 mol/L KCl (12.88 mS)
0
1.81
1.81
1.78
15
1.92
1.91
1.88
35
2.04
2.02
2.03
45
2.08
2.06
2.02
100
2.27
2.22
2.14
Solution
(%/°C)
Solution
(%/°C)
NaCl Saline solution
2.12
1.5% Hydrofluoric acid
7.20
5% NaOH Solution
1.72
Acids
0.9 - 1.60
Diluted ammonia solution
1.88
Bases
1.7 – 2.2
10% Hydrochloric acid solution
1.32
Salts
2.2 - 3.0
5% Sulfuric acid solution
0.96
Drinking water
2.0

XS Instruments 7 Vio Specifications

General

Brand	XS Instruments
Model	7 Vio
Category	Measuring Instruments
Language	English