Temperature Compensation; Non-Linear Temperature Compensation According To En 27888 - Tintometer Lovibond SD 325 Con Mode D'emploi

Display ranges of TDS / dry filtrate residue
The TDS (total dissolved solids) measurement is used along with the conductivity and a
conversion factor (<SEt PArA>: C.tdS) to determine the dry filtrate residue (evaporation
residue). The display is shown in ppm (1 ppm = 1 mg/litre).
Range 1
CELL
– rAnG
0.01 0.000–5.000 mg/
litre
0.1 0.00–50.00 mg/litre 0.0–500.0 mg/
1 0.0–500.0 mg/litre 0–5,000 mg/
10 0–5,000 mg/litre
Display value of TDS = measured conductivity * C.tdS
Approximately applicable:
C.tdS conversion factor
0.50*
0.65–0.70*
*The specified factors are intended solely for guidance.
Salt content / salinity
In "SAL" measuring mode, the salinity (salt content) of seawater can be determined. Standard
seawater has a salinity of 35‰ (35 g salt per 1 kg seawater). The data are generally displayed
without units in ‰ (≈ g/kg). Another commonly used term is "PSU" (practical salinity unit).
The salinity measurement has its own temperature compensation, which is taken into account
in the display in the instrument.

5.7 Temperature compensation

The conductivity of aqueous solutions is temperature dependent. The conductivity of a so-
lution can be calculated back to a standard reference temperature by means of temperature
compensation. Commonly used reference temperatures for comparing conductivities are
25° C and 20° C. If the measurement is carried out at a set reference temperature, no tem-
perature compensation is required.

5.7.1 Non-linear temperature compensation according to EN 27888

For most applications, for example in the field of fish breeding and the measurement of surface
and drinking water, the non-linear temperature compensation for natural water is sufficiently
accurate. The usual reference temperature is 25°C. (<SEt PArA>: t.Cor = nLF)
The recommended conductivity range for non-linear temperature compensation:
60 to 1,000 µS/cm
58
2
0.00–50.00 mg/
litre
litre
litre
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Example
• Monovalent salts (e.g. NaCl, KCl)
• Natural water / surface water, drinking water
• Wastewater
3 4
0.0–500.0 mg/ 0–5,000 mg/
litre litre
0–5,000 mg/litre ---
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SD_325_Con_1 06/2020