- -
24
Conductivity measurement
The HD 98569 works with combined conductivity/temperature probes with SICRAM (right input).
The 4 wire Pt100 temperature sensor is used for automatic compensation of conductivity.
If a temperature only probe is connected (to the pH/mV or O
2
inputs), the measured
temperature value becomes the reference value, and has priority on the one supplied by the
combined conductivity probe.
SICRAM conductivity probes
The combined conductivity/temperature probe with SICRAM is fitted with a Pt100 temperature
sensor and an electronic module. The module has a memory circuit that enables the instrument to
recognize the type of probe connected. It stores also the serial number, the factory calibration of
the Pt100 sensor, the manufacturing date and the last calibration performed by the user.
The SICRAM conductivity probes use the cell constant saved in the probe’s memory: a new
calibration updates its value.
The instrument obtains the following from the measurement of conductivity:
•
the liquid resistivity measurement (
Ω⋅
cm, k
Ω⋅
cm, M
Ω⋅
cm),
•
the concentration of total dissolved solids (TDS) according to the
χ
/TDS conversion factor,
which can be modified using the menu,
•
the salinity (NaCl quantity in the solution, expressed in g/l).
By repeatedly pressing “
F3 = cond.
” you can select the quantity.
The conductivity probes must be periodically calibrated. To facilitate this operation, four standard
calibration solutions are automatically recognized by the instrument:
•
0.001 Molar KCl solution (147
μ
S/cm @25°C),
•
0.01 Molar KCl solution (1413
μ
S/cm @25°C),
•
0.1 Molar KCl solution (12880
μ
S/cm @25°C),
•
1 Molar KCl solution (111800
μ
S/cm @25°C),
User calibration of the temperature sensors is not required
.
The probes are detected during turn on, and this cannot be performed when the instrument
is already on, therefore if a probe is connected and the instrument is on, it is necessary to
turn it off and on
.
Standard SP06TS probe
The 4-electrode conductivity/temperature combined probe, code SP06TS, is formed by a cell
delimited by a bell in Pocan.
A positioning key, present in the probe's end part, orients the bell correctly when the probe is
introduced. For cleaning, simply pull the bell along the probe's axis
without rotating it
.
It is not
possible to perform measurements without this bell.
The probe is recommended for non-heavy general use. The temperature measuring range is
0°C…+90°C.
