100 AWT420 | UNIVERSAL 4-WIRE, DUAL-INPUT TRANSMITTER | OI/AWT420-EN REV. B
…Appendix B 2-electrode conductivity calculations
…Automatic temperature compensation
Calculation of temperature coefficient
The temperature coefficient of a solution can be obtained
experimentally by taking non-temperature compensated
conductivity measurements at two temperatures and applying
the following expression:
G – G
G (t – 25) – G (t – 25)
t2 t1
=
Where:
Gt2
temperature of t2
Gt1
temperature of t1
One of these measurements could be made at the ambient
temperature and the other obtained by heating the sample.
For ultra pure water applications the temperature
compensation equation becomes,
G – G
[G (t – 25) – G (t – 25)]
imp1 imp2
Where:
Gimp1 t1upw1
Gimp2 t2upw2
Relationship between conductivity and total
dissolved solids (TDS) measurement
-1
properties of the solution being measured.
In simple solutions where only one electrolyte is present, the
case of sodium chloride. However, in complex solutions where
more than one electrolyte is present, the ratio is not calculated
easily and can be reliably determined only by laboratory testing,
e.g., precipitation and weighing. The ratio in these cases varies
between approximately 0.4 and 0.8, depending on the chemical
constituents, (e.g., the ratio for sea water is about 0.6) and is
constant only when the chemical ratios remain constant
throughout a particular process.
refer to the supplier of the particular chemical treatment being
used.
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