Endress+Hauser Viomax CAS51D, Operating Instructions Manual

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Viomax CAS51D Operation
Hauser 27
If you use three or more concentration values for calibration, a completely new calibration
function is calculated that no longer takes the original factory calibration data record into
account.
Give your calibration data records meaningful and useful names. For example, the
name could contain the name of the application on which your data record was
originally based. This makes it easier for you to distinguish between different data
records.
7.1.3 Stability criterion
During the calibration process, the measured values are checked to ensure that they
remain constant.
You use the stability criterion to define maximum deviations during a calibration. Only a
measured value within the specified deviation is accepted.
The stability criterion includes:
• The maximum permitted deviation in temperature measurement
• The maximum permitted deviation in measured value as a %
• the minimum time frame in which these values must be maintained
If the measured value or temperature deviate more than is permitted in the specified time
frame, this calibration point becomes invalid and a warning is issued.
The stability criteria are used to monitor the quality of the individual calibration points in
the course of the calibration process. The aim is to achieve the best possible calibration
quality in the shortest possible time frame while taking external conditions into account.
• For high-precision calibrations in the laboratory, the maximum deviation permitted in
the measured value can be kept as small as possible and the time frame selected can be
as long as possible..
• For calibrations in the field in adverse weather and environmental conditions, the
maximum deviation permitted in the measured value can be kept suitably large and the
time frame selected can be kept suitably short.
Operating Instructions Memosens inputs BA01245C
7.1.4 Determining the reference values in the laboratory
Nitrate sensor
1. Take a representative sample of the medium.
 Outlet water is very suitable for obtaining a representative sample. In this case,
you do not have to carry out the subsequent step concerning value stabilization.
2. Take suitable measures to ensure that the process of nitrate reduction in the sample
does not progress any further, such as immediate filtration (0.45 µm) of the sample
as per DIN 38402.
3. Determine the concentration of nitrate in the sample using the laboratory method
(for example, by colorimetric means using a cuvette test
‐
the standard method as per
DIN 38405 Part 9).
SAC sensor
1. Take a representative sample of the medium.
 Outlet water is very suitable for obtaining a representative sample. In this case,
you do not have to carry out the subsequent step concerning value stabilization.
2. Take suitable measures to ensure that the process of biological and chemical
reduction in the sample does not progress any further.
3. Determine the measured values of your sample array using the laboratory method
(for example, by colorimetric means using a cuvette test).