Reference Temperature, Temperature Compensation And Temperature Coefficient - Thermo Scientific Orion Versa Star Pro User Manual

Thermo Scientific
Reference Temperature, Temperature Compensation and
Temperature Coefficient
Versa Star Pro meters with a conductivity module offer several options for temperature
compensated conductivity measurements. Temperature has a large effect on the conductivity
value of a solution. The temperature compensation feature allows the meter to use the sample
conductivity and temperature readings to calculate and display the conductivity that the sample
would be expected to have at a selected reference temperature, such as 25 °C. To accurately
use the temperature compensation feature, select the proper type of temperature compensation
for the samples to be measured; set the required reference temperature as 5 °C, 10 °C, 15 °C,
20 °C or 25 °C; and use a conductivity probe with built-in ATC temperature probe.
The options for temperature compensation are:

Linear – uses the temperature coefficient value to apply a constant percent correction
factor to every degree change in temperature. A few common linear coefficient values are:
Solution (25 °C to 50 °C)
Sugar Syrup
Ultra Pure Water
98 % Sulfuric Acid
Salt (NaCl)
Dilute Ammonia
5 % NaOH
10 % HCl
5 % Sulfuric Acid

nLFn (non-linear ultra-pure non-degassed water) – applies a non-constant correction factor
to pure water samples that have a varying response to changes in temperature. This mode
is for temperature compensated readings of low conductivity waters that are in equilibrium
with the carbon dioxide in air, such as pure waters reading near 1 μS/cm at 25 °C and
natural waters having a composition comparable to natural ground, well or surface waters.

nLFu (non-linear ultra-pure degassed water) – applies a non-constant correction factor to
pure water samples that have a varying response to changes in temperature. This mode is
for temperature compensated readings of ultra-pure water that contains no air and no
carbon dioxide, such as ultra-pure water (18 megohms resistance or higher) directly from
the source without aeration.

EP – no temperature correction is applied (temperature compensation turned off) and a
warning is displayed if the measured conductivity value is over the EP requirement for pure
water at the measured sample temperature.

Off - no temperature correction is applied and the actual conductivity value is displayed at
the measured sample temperature.

Appendix A Channel Specific Settings and Features
Temperature Coefficient (% / °C)
5.64
4.55
2.84
2.12
1.88
1.72
1.32
0.96
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