LABEC M-MIA-CC - Manual (Page 31)

Ultrasonic milk analyser
Operation manual 23.08.10 29/98
6. MAKING CORRECTIONS AND RECALLIBRATION OF THE
DEVICE
At least once monthly check the correctness of the results and need of
corrections and calibration.
In the process of work with the analyser there is a possibility the results to
start differing between the data for some of the measuring parameters when
measured with the milk analyser and the corresponding reference method of
analyses (Gerber for fat, Kjeldhal for proteins etc). In order to establish the
possible discrepancy and to correct the readings of the milk analyser do the
following:
6.1. Taking samples and preparation of samples for checking the
accuracy of the milk analyser, making corrections and recalibration
This is a basic moment for the correct checking the accuracy of the analyser
and for making correct and precise correction and calibration. It is
accomplished according Appendix Taking and preparation of samples for
checking correctness of the milk analyser, making corrections and
recalibration.
6.2. Determination the type of the discrepancy:
6.2.1. Making measurements
Make measurements with different samples (not less than 3) with known
values of a separate parameter (for example fat content), determined by the
known reference methods of analyses (for example Gerber's method for
determination of fat content). For more accuracy it is recommended among
these samples to be also such with values, close to the lowest and highest
bounds for the measured parameters.
Make 5-time measurement for each of the samples. Calculate the average
value for each sample parameter, without taking into consideration the first
measurement for each sample.
6.2.2. Analyzing the measurement results
Make comparison between the values of the parameter from the reference
sample and measured with the analyser. Make analyses of the difference
received.