NAVI D-25 Instruction Manual page 204

● New units (SI units)
● Temperature compensation
D-52/53/54/55
New measurement units, called SI units, have come into
use in recent years. Accordingly, the meter also uses SI
units. The following conversion table is provided for
people who are used to using the conventional kind of
conductivity meter. Note that along with the change in
unit systems, the measurement values and cell counts
have also changed.
Former
units
Cell constant
1 cm
0.1 cm
10 cm
10 µS/cm
Measurement
value
1 mS/cm
100 mS/cm ⇒ 10 S/m
The conductivity of a solution generally varies greatly,
depending on the temperature of the solution. Because
the conductivity of a solution is based on its ION
conductivity, as explained above, the higher the
temperature of the solution the more active its ions and
the higher its conductivity. Using a given temperature as
the standard (and calling that the standard temperature),
the "temperature coefficient" expresses how much
change (expressed in %) occurs in conductivity when
the temperature of the solution changes by 1ºC. The
temperature coefficient is expressed in units of "%/ºC
(standard temperature)." This temperature coefficient is
found by assuming that the conductivity of the sample
changes linearly in relation to temperature, whereas the
change in conductivity of an actual sample, strictly
speaking, follows a curve. The shape of this curve
changes, depending on the kind of sample being
measured. Most solutions, however, are said to
generally have a temperature coefficient of 2%/ºC (25ºC
7.4 Conductivity measurement
⇒ SI units
⇒ 100 m
-1
-1 ⇒ 10 m
⇒ 1000 m
-1
⇒ 1 mS/m
⇒ 100 mS/m
7 Reference
-1
-1
-1
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