Hach-Lange NISE sc - Manual (Page 29)

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Operation
4.6.4.2 Value correction 1
The one-point value correction VALUE CORR. 1 offers the option of retrospectively
performing a matrix correction at one point ( MATRIX1 ).
1. Take several samples with different concentrations on various days, preferably within
one week. Analyze the samples in the laboratory. During the time the samples are
being taken, the sample temperature should be around a maximum of 5 °C, as
temperature changes are not taken into account in the value correction.
2. Make a note of the two values measured in the samples and displayed for the
parameters to be corrected (ammonium and potassium values, or nitrate and chloride
values)
3. Also note the laboratory values measured for ammonium or nitrate.
These three values form the correction point.
4. From the values taken, select a correction point that lies in the middle of the expected
concentration range.
5. Go to the sensor menu and select CALIBRATE > MATRIXCORR > VALUE CORR. 1 and
confirm by pressing ENTER .
6. Select the parameter 1 (NH
4
–N or NO
3
–N) that requires correction.
Note: The example opposite shows the NH
4
-N and K correction of the AN-ISE sc probe.
7. Enter the three values for the sought correction point and confirm with ENTRY
COMPLETE to activate the correction.
Correction result CORR-RESULT is shown.
Note: If a correction does not produce a successful result, calculations are made with the previous
correction.
After successful completion of value correction, the corrected value is shown as the display value for
ammonium or nitrate the next time the menu is opened.
4.6.4.3 Value correction 2
The two-point value correction VALUE CORR. 2 makes it possible to perform a subsequent
2-point correction ( MATRIX2 ) to achieve higher accuracy for a larger concentration range.
Note: Value correction 2 and MATRIX 2 are comparable from a calculation perspective.
1. Take several samples on various days with different concentrations, preferably within
a week, and perform an analysis of the samples in the laboratory. During the time the
samples are being taken, the sample temperature should be around a maximum of 5
°C, as temperature changes are not taken into account in the value correction.
Note: The MATRIX CORR. 2 concentrations should be within a range greater than half a
decade. The following formula can assist in the calculation of the half decade:
2. Make a note of the two values measured with the sensor in the samples and displayed
for the parameters to be corrected (ammonium and potassium values, or nitrate and
chloride values).
3. Also note the laboratory value measured for ammonium or nitrate.
CALIBRATE
MATRIX CORR
FURTHER CORR.
INFORMATION
VALUE POINT
AN–ISE SC NH4–N
AN–ISE SC K
LAB NH4–N
ENTRY COMPLETE
1 Applies to AN-ISE sc
CALIBRATE
MATRIX CORR
FURTHER CORR.
INFORMATION
Conc2 >=
Conc1 Ч 10
2