Hach-Lange NO3D sc Nitrate Sensor - Manual (Page 23)

23
Operation
which includes a multi-point nitrate and chloride calibration and the
cross sensitivity of chloride on nitrate.
When the code is entered, the sensor is completely calibrated. It is
recommended to perform a matrix correction to correct the
cartridge on the specific matrix.
Please use the default sensor code, if the specific sensor code is
not available.
To change the sensor code:
1. Select SENSOR SETUP>NO3D SC>
CALIBRATE>CAL.CONFIG.>SENSORCODE
2. Enter the 16 character sensor code.
3. Press ENTER to confirm and activate the sensor code.
The day meter is set to zero.
All old calibration data are now overwritten with the new calibration
data from the sensor code. The sensor code data are checked by
the system. If an error is indicated, check the sensor code and
repeat the entry of the sensor code if necessary.
4.6.2 Matrix correction overview
With the NO3D sc sensor, there are various options ( Table 1 ) for
correcting the measured value with laboratory reference values.
For the laboratory reference value, a sample is taken for laboratory
analysis and the measurement value at that time is stored.
Depending on the parameter set, the laboratory reference value of
the water sample is stored as nitrate nitrogen (NO
3
–N) or as nitrate
(NO
3
). This laboratory reference value replaces the prior value
measured by the sensor.
Table 1 Correction options for the NO3D sc sensor
Correction Option Application
MATX1
The most commonly used Matrix correction. It performs a 1 point matrix correction (offset
adjustment) for nitrate (
4.6.3.1 on page 24 ).
MATX1 CL-
With the MATX1 CL- the nitrate value will be corrected as with the MATX1 and in addition the
chloride value can be corrected. This is necessary if a higher precision of the nitrate value is required
as the chloride value will interfere with the nitrate measurement (
4.6.3.2 on page 24 ).
MATX2
Where there is a dynamic process with a large nitrate fluctuation (at least 1/2 decade between the
lowest and highest concentration)
1 , it is recommended to perform the MATX2 ( 4.6.3.3 on page 25 ).
MATX2 CL-
Where there is a dynamic process with a large nitrate fluctuation (at least 1/2 decade between the
lowest and highest concentration)
1 and chloride value is to be corrected, it is recommended to
perform the MATX2 CL- ( 4.6.3.4 on page 26 ).
VALUE CORR
The nitrate and chloride displayed value and the nitrate laboratory value can be entered for two
points. This is a different way to perform a MATX2 Correction. Here, for two points, the displayed
nitrate and chloride values and the nitrate laboratory value are entered via an input screen.
PREVIOUS CAL Activation of one of the last 4 matrix and value corrections performed.
FACTORY CAL
If the current sensor code is no longer available, average data for the sensor can be activated using
FACTORY CAL.
1 Examples of a half decade: The nitrate nitrogen concentration moves between 1 and 5 mg NO
3
–N or
between 5 and 25 mg/L NO
3
–N ( Conc 2 = (Conc 1 x 10)/2 ).