H87.0.0X.6C-01
Operating manual G 7500 Series
page 16 of 34
6.5 Temperature compensation
The conductivity of aqueous solutions depends on its temperature. The temperature
dependency is strongly dependent on the type of solution. The temperature
compensation recalculates solutions’ conductivity to a consistent reference
temperature. The most common reference temperature is 25 °C, but 20 °C can also
be selected.
6.5.1
Temperature compensation “NLF” according to EN 27888
For most applications (e.g. in the area of fish farming, surface or drinking water
measurements, etc.) the non-linear temperature compensation for natural water
(“nLF”, according to EN 27888) is sufficiently accurate.
Recommended application range of nLF-compensation: between 60 µS/cm and 1000
µS/cm.
6.5.2 Linear temperature compensation
If the actual function needed for exact temperature compensation is not known,
“linear temperature compensation” is normally selected (Menu, t.Cor = Lin, t.Lin
corresponds
TK
lin
), i.e. one assumes that the actual temperature dependency at the
considered concentration range is approximately equal:
LF
Tref
=
LF
Tx
1 +
𝑇𝐾
𝑙𝑖𝑛
100%
• (Tx − Tref)
Temperature coefficient of about 2.0 %/K are most common.
A temperature coefficient can be determined for example by measuring a solution
with deactivated temperature compensation at two different temperatures (T1 and
T2).
𝑇𝐾
𝑙𝑖𝑛
=
(LF
T1
− LF
T2
) • 100%
(T1 − T2) • LF
T1
TK
lin
is the value input at the menu
LF
T1
conductivity at temperature T1
LF
T2
conductivity at temperature T2
