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<Reference 1>
● Display of protein's constant moisture basis (CM)
The protein value to be displayed with this unit indicates the percentage of
constituent over a whole measuring object including moisture. It is useful,
for example, when calculating the weight of protein contained in the meas-
ured grain. However, when comparing the protein value in the multiple
targets, there may be a case it is more convenient to assume that the
targets have the fixed moisture value. The CM display of the protein value is
based on this concept. The CM indicates the converted protein value
assuming that the moisture value of the measurement targets is a certain
given value ("@Moisture%" with AN-920). When the given moisture value is
"0%", it is called "Dry Moisture basis" (DM). The conversion formula is as
follows. To display correct "Protein CM", the calibration curves of "Protein"
and "Moisture" and "@Moisture%" needs to be set properly.
Protein × (100-@Moisture%)
Protein CM =
100 - Moisture
<Appendix> To use the unit in the best accuracy
Regularly check the standard samples in order to minimize the affects to the measurement by the
changes that may occur in the time course. In addition, the standard sample should be checked
when the measurement environment is changed, the operator is changed, after a power failure, and
when the measured value seems not reliable.
■ Check using standard samples
● What is standard sample?
A standard sample is the sample whose standard values have been calibrated before shipment.
Each standard value is indicated on the top of the standard sample case.
● Storage
• Store the sample in the cool dark place (5 to 10°C) such as in the refrigerator.
• Never store the sample in the freezer. The sample will be frozen.
• Other than the appropriate storage, it may cause a change to the standard value.
• The validation period indicated on the standard sample is applicable as long as the sample is
appropriately stored.
Use only the sample within the validation period.
● How to check using standard samples
(1) Take out the sample from the cool dark place before a half day before the measurement.
(2) Place the AN-920 main unit and the standard sample in a same place to have them thermally
stabilized.
(3) Measure the standard sample for three to five times, and calculate the average value.
(4) Compare the measured composition value with the standard value of each composition.
Example:
Reference
Average of measurement values
Difference
Standard
sample
16.0%
16.2%
0.2%
In this example, the difference is "0.2". Therefore, a bias adjustment is not necessary in the
standard use. If the difference is over "0.2", repeat the above procedure and compare the
values again. As a result, if the difference is over "0.2", a bias adjustment is required. Each
composition has different limit value. We recommend the following an a reference. Define
the limit value according to the operating environment.
<Reference 2>
● Display of Quality Evaluation Value
(Q.E.V.)
While "Protein CM" is not displayed, the Q.E.V.
will be calculated from the measured protein
value (not CM) and the moisture included value.
When "@Moisture%" is set less than 10% and
"Protein CM" is displayed, the Q.E.V. will be
calculated from the measured protein value (not
CM) and the moisture included value. When "@
Moisture%" is set more than 10% and "Protein
CM" is displayed, the Q.E.V. will be calculated
replacing "Protein" with "Protein CM" and "Mois-
ture" with "@Moisture%".
Composition
Reference limit value
Protein
0.3%
Moisture content
0.2%
Amylose (ref.)
1.0%
