User Manual

<Appendix 2 For SC (Conductivity)>
App.2-1
IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00
Appendix 2 For SC (Conductivity)
n Temperature compensation
The conductivity of a solution is very dependent on temperature. Typically for every 1°C
changeintemperaturethesolutionconductivitywillchangebyapproximately2%.Theeffectof
temperature varies from one solution to another and is determined by several factors like solution
composition,concentrationandtemperaturerange.Acoefcient(α)isintroducedtoexpressthe
amountoftemperatureinuencein%changeinconductivity/°C.Inalmostallapplicationsthis
temperatureinuencemustbecompensatedbeforetheconductivityreadingcanbeinterpreted
as an accurate measure of concentration or purity.
l NaCl (standard temperature compensation)
The FLXA21 has the default temperature compensation function based on a sodium chloride
(NaCl)solution.Thisfunctioncanbeusedforvariousapplicationsandiscompatiblewiththe
NaClcompensationfunctionoftypicallaboratoryorportableinstruments.
Table 1 NaCl compensation according to IEC 60746-3 with Tref. = 25°C
Temperature
(°C)
Ratio*
Temperature compensa-
tioncoefcient(%/°C)
Temperature
(°C)
Ratio*
Temperature compensa-
tioncoefcient(%/°C)
0 0.54 1.8 100 2.68 2.2
10 0.72 1.9 110 2.90 2.2
20 0.90 2.0 120 3.12 2.2
25 1.00 — 130 3.34 2.2
30 1.10 2.0 140 3.56 2.2
40 1.31 2.0 150 3.79 2.2
50 1.53 2.1 160 4.03 2.2
60 1.76 2.2 170 4.23 2.2
70 1.99 2.2 180 4.42 2.2
80 2.22 2.2 190 4.61 2.2
90 2.45 2.2 200 4.78 2.2
*: Theratiooftheconductivityatrespectivetemperaturestotheconductivityatthereferencetemperature.
l Temperaturecompensationcoefcient(TC)
Setthetemperaturecompensationcoefcientbasedonthedegreeofinuenceoftemperature
on the conductivity (%/°C).
Ifthetemperaturecompensationcoefcientofthesamplesolutionisknownfromlaboratory
experimentsorhasbeenpreviouslydetermined,enterthevalue.
Thesettingrangeisbetween0.00and10.0%.Bycombiningwiththereferencetemperature
setting, a linear compensation function can be obtained. This is applicable to all kinds of chemical
solution.
<Congurecalculatedtemperaturecoefcient(TC).>
Follow routing
Commissioning>>Measurementsetup>>Temp.compensation>>T.C.
Enterthetemperaturecoefcientcalculatedfromthefollowingformula:
App.
SC