XS Instruments 8+Serie Manual De Instrucciones página 25

• Once the calibration has expired, "
continue to make measurements.
P2.5 Last Calibration Cond Data
Access this menu to get information about the last calibration performed.
• "View" (Factory default): a report is shown on the display with the following information about the
current calibration: CAL DATE and HOUR / TEMP / MEASURING UNIT / ID SENSOR / CELL CONSTANT
for every range.
"Print": connect the printer to the device through RS232 port (see outputs connections) to print the
•
calibration report directly on paper format.
P2.6 and P2.7 Temperature compensation in conductivity measurement it is not to be confused with
the temperature compensation for pH measurement.
In a conductivity measurement the value show on the display is the conductivity calculated at
•
the reference temperature. So, it is corrected by the effect of temperature on the sample.
Instead, in a pH measurement the value show is the pH at the displayed temperature. Here the
•
temperature compensation involves the adaptation of the slope and the electrode offset at the
measured temperature.
P2.6 Reference temperature for Cond
The conductivity measurement is strongly temperature dependent.
If the temperature of a sample increases, its viscosity decreases and this leads to an increase in ion mobility
and of the measured conductivity, despite the concentration remains constant.
For each conductivity measurement the temperature to which it is related must be specified, otherwise it is
a worthless result. Generally, the temperature refers to 25 °C or more rarely to 20 °C.
This device measures the conductivity at the actual temperature (ATC or MTC) and then convert it to the
reference temperature using the correction algorithm chosen in P2.7 program.
• Enter this setup menu to set the temperature to which the conductivity measurement is to be reported.
• The device is able to refer the conductivity from 15 to 30 °C. As factory default setting is 25°C which is
fine for most of the analysis.
P2.7 Temperature compensation factor
It is important to know the dependence on temperature (percentage variation of conductivity every °C) of
the sample. To simplify the complex relationship between conductivity, temperature and ionic
concentration different compensation methods can be used
Linear Coefficent 0.00...10.0 %/°C -default 1.91 %/°C - For the compensation of medium and high
•
conductivity solutions, linear compensation can be used. The default factory value is fine for most of
the routine measures.
Compensation coefficients for special solutions and for groups of substances are shown in the following
table.
Sample
NaCl Saline Solution
5% NaOH Solution
Diluted ammonia solution
10% Hydrochloric acid solution
5% Solforic acid solution
UM Serie 880 EN rev.2 30.07.2020
" icon will appear on the display, anyway the user may
(%/°C) Sample
2.12 1.5% Hydrofluoric acid
1.72 Acids
1.88 Bases
1.32 Salts
0.96 Drinking water
24
(%/°C)
7.20
0.9 - 1.60
1.7 – 2.2
2.2 - 3.0
2.0
EN