Hach-Lange DR 3900 User Manual - Manual (Page 60)

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Standard programs
5.4.6.1 Change of the default setting of the chemical form
1. In the result display, press Options>More>Chemical Form.
2. A list of available evaluation forms appear. Select the new
default setting.
3. Press Save as Default.
The current result and all further readings will be displayed in the
new chemical form.
5.4.7 Run a reagent blank
Some of the stored tests/methods include the "Reagent Blank"
function. This enables the reagent blank value to be measured
and then taken into account in calculating the reading result.
Reading/analysis of a reagent blank:
1. Prepare the test corresponding to the
specification/procedural instructions. Use distilled water
instead of a sample to determine the reagent blank value.
2. Select the test. Insert the zero solution into the cell
compartment, if required by the procedural instructions.
Press Zero.
3. Insert the prepared sample cell into the cell compartment.
Press Read. The result will be displayed.
4. Press Options>More>Reagent Blank.
5. Press On to highlight the Reagent Blank function.
6. The concentration shown on the button is the reading of the
reagent blank. To use this value for more analyses of this
parameter, press OK.
7. To change the value displayed on the button, press the
button. Use the alphanumeric keypad to enter the new value.
8. Next press OK.
Note: The "Reagent Blank" function is deactivated when the reading
program is left. To use the same blank value later for other tests using
the same reagent lot, enter the value per step
7 .
Note: The results calculated using the reagent blank value must lie
within the limits of the measuring range of the test/method.