Commissioning
Liquisys M CUM223/253
66
Hauser
A different dilution ratio should be selected for very high-absorption media to achieve
accurate calibration results. Instead of 100 % – 33 % – 10 %, you can use dilution ratios of
100 % – 20 % – 5 % or 100% – 10 % – 3.3 %.
If the scattered light of a light sample hits a sensor that is calibrated for a dark medium, it
can happen that the signal value is so high that it is above the calibration curve.
Three-point correction (Corr)
If the calibration was performed with an unknown sample concentration but with a defined
dilution, the correct value determined afterwards in the laboratory is entered here.
Edit calibration (Edit)
If each of the samples has been determined afterwards in the laboratory, the correction for
the calibration is entered here.
Installation adjustment (Refl)
In installation adjustment, backscatter from the immediate sensor environment is
compensated. Installation adjustment must be performed with a medium whose turbidity is
lower than 2 FNU or 5 ppm.
One-point calibration (1–Pt)
In the area of TS/concentration measurement, one-point calibration is used to change the
conversion factor (field C166). The slopes are not changed.
In the FNU range, the two slope values are adjusted by a one-point calibration. This is
possible because the conversion factor in the FNU range is always 1 and the editing range is
limited to 4000 FNU. In this way, the two curves are always increasing and the calibration
remains clear.
In the ppm range, the slope values are adjusted up to 500 ppm. For higher values, the
conversion factor is changed.
Calibration data (Data)
Here, you can display the calibration points 1 to 3, slope 1 and 2 and the conversion factor.
With three-point calibration, the curves used in the algorithm are adjusted as precisely as
possible using the data points acquired. The difference between the ideal curve of the
algorithm and the three actual calibration points can be found as a correction factor in the
C161, C162 and C163 fields of the data function. The correction values are indicated in %.
The values should be as close to 100 % as possible. Values from 70 to 80 % are acceptable.
50 % in one or two calibration points clearly indicates a problematic calibration. A warning
(E084) is output here for this reason. This can mean that significant deviations can occur
between the calibration points. The calibration points themselves are always retrieved
correctly.
