Mettler Toledo SevenGo pro SG7 Mode D'emploi page 18

Menus
Ref. temp.
You can select between the reference temperatures of 20 °C or 25 °C. The conductivity of the sample is
referenced to the temperature you select during the reading.
Temp. comp.
"Linear"
The conductivity of a solution increases when the temperature increases. With most solutions, a linear
interrelationship between conductivity and temperature is given. In such cases, select the linear correction
method.
The input window for the temperature coefficient (0-10%/°C) appears.
The measured conductivity is corrected and displayed using the following formula:
G =G /(1+(α(T-T ))/100)
TRef T Ref
where
G conductivity measured at temperature T (mS/cm)
T
G conductivity (mS/cm) displayed by the meter, calculated back to the reference temperature T
Tref
linear temperature coefficient (%/°C)
α
T measured temperature (°C)
T reference temperature (20 °C or 25 °C)
Ref
Note
When α-coefficient = 0 no temperature correction is applied. This means you can work according to USP
rules.
"Non-linear"
The conductivity of natural waters shows strong non-linear temperature behavior. For this reason, we recom-
mend non-linear correction when measuring natural waters.
The measured conductivity is multiplied by the factor f
and thus referenced to the temperature of 25 °C:
G = G · f
T25 T 25
If another reference temperature is to be referenced, e.g. 20 °C, the conductivity referenced from 25 °C is
divided by 1.116 (see f
G = (G · f )/1.116
T20 T 25
Note
Conductivity measurements of natural waters can only be performed at temperatures ranging from 0 °C to
35.9 °C. Otherwise, the warning "Temp. out of nLF range" appears.
TDS factor
The input window for the TDS factor appears.
TDS is the concentration of dissolved solids which pass through a filter with a pore size of 0.45 microns.
These are typically the following components: carbonate, bicarbonate, chloride, sulfate, phosphate, nitrate,
calcium, magnesium, sodium, organic ions and other ions.
TDS (mg/L) is calculated by multiplying the conductivity value (mS/cm) by the TDS factor.
14
for 20.0 °C)
25
for the measured temperature (see table in Appendix)
25
METTLER TOLEDO SevenGo pro™ conductivity
Ref