XS Instruments 70 Vio Series, Инструкция по эксплуатации

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30
Rev. 1 24/01/2020
EN
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
To determine the calibration coefficient of a solution, the following formula is applied:
𝑡𝑡𝑡𝑡 = 100 𝑥𝑥
𝐶𝐶
𝑇𝑇2
− 𝐶𝐶
𝑇𝑇1
𝐶𝐶
𝑇𝑇1
( 𝑇𝑇
2
− 25) − 𝐶𝐶
𝑇𝑇2
( 𝑇𝑇
1
− 25)
Where tc is the temperature coefficient to be calculated, C
T1
and C
T2
are the Conductivity at temperature 1
(T1) and at temperature 2 (T2).
Each result with “correct” temperature is plagued by an error caused by the temperature coefficient. The
better the temperature correction, the lower the error. The only way to eliminate this error is not to use the
correction factor, acting directly on the sample temperature.
Select 0.00% / °C as the temperature coefficient to deactivate the compensation. The displayed Conductivity
value refers to the temperature value measured by the probe and not related to a reference temperature.
P3.6 COND calibration data
Access this menu to get information on the last calibration performed. The following screens will
automatically scroll on the display:
• First screen: CALIBRATION DATE and TIME and beakers indicating the buffers used.
• Second and possibly third, fourth and fifth screens: value of the actual cell constant in the
measurement range indicated by the beaker.
Note : The instrument accepts calibrations with a maximum tolerance of 40% on the nominal value of the
cell constant only.
P3.7 COND Calibration expiration
Access this menu to set a calibration deadline; this option is fundamental in GLP protocols.
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