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Appendix F - “Temperature compensation”
Conductivity measurements are temperature dependent. The degree to which temperature affects conductivity varies
from solution to solution and can be calculated using the following formula:
Gt = Gtcal {1 + a(T-Tcal)}
where: Gt = conductivity at any temperature T in °C, Gtcal = conductivity at calibration temperature Tcal in °C, a =
temperature coefficient of solution at Tcal in °C.
Substance at 25°C Concentration Alpha (a)
HCl 10 wt% 1.56
KCl 10 wt% 1.88
H2SO4 50 wt% 1.93
NaCl 10 wt% 2.14
Common alphas (a) are listed in the table above. To determine that (a) of other solutions, simply measure conductivity
at a range of temperatures and graph the change in conductivity versus the change in temperature. Divide the slope
of the graph by Gtcal to get a.
Temperature compensation (Alpha) can be changed within 0.0% and 5.0%. It should be set according to measured
chemical properties. If a temperature probe is installed choose “Enable” for “Automatic”. Otherwise select “Disable”
and enter a temperature value in “Temperature” field.
Note: “Temperarure” field is not visible if “Automatic” has been set on “Enable”.
To end procedure move cursor on “OK” and press wheel to proceed to “Save” request screen. Move wheel on
“YES” to save or “NO” to discard changes.
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