Hach-Lange FP 360 sc User Manual - Manual (Page 21)

21
Operation
6. Enter the factor as the slope (refer to section 4.5.4.1 on page 21 ).
Lab value: 4.0 ppm oil 
Measurement value shown 1
1 At the time of sampling
: 2.4 ppm oil 
Calculated factor: 1.67
Lab value: 420 ppb PAH 
Measurement value shown 1 : 120 ppb PAH 
Calculated factor: 3.5
It is advisable to adjust the slope if the following conditions apply:
• If the measuring sample is PAH-/oil free, the measurement value must almost be zero.
• The factors calculated from the lab values must enable a sensible average value to be
derived.
If these conditions do not apply, do a multi-point calibration.
Note: If both the zero point and the slope must be changed, use a 2-point calibration (refer to
section
4.5.4.3 on page 22 ).
4.5.2.2 Multi-point calibration
In the event of a multi-point calibration, enter the lab value as the target value and the
value shown as the actual value. Make sure that all values are entered in the same unit,
e.g. oil in ppm. (refer to section
4.5.4.3 on page 22 ).
4.5.3 Check the zero point
• Medium: ultra-pure water
• Target value: < 1 ppb. Clean the window in the event of deviations.
Use a glass container (not plastic) large enough to enable the measurement to be taken
with an 8 to 10 cm distance between the measurement window and the base (e.g. a
1000 mL glass beaker). Place a black, non-reflective underlay under the container and
switch off artificial lights during the measurement process.
Note: In air, the measurement value displayed is not exactly zero due to reflections on the window
surface. This is standard sensor behavior and not an indicator of malfunction.
Note: Always use ultra-pure water. Distilled water and demineralized water are not suitable as these
can contain organic compounds.
4.5.4 Adjustment of slope and zero point; multi-point calibration
4.5.4.1 Adjust the slope (FACTOR)
1. Open the MAIN MENU.
2. Select SENSOR SETUP and confirm.
3. Select the corresponding sensor and confirm.
4. Select CALIBRATE and confirm.
5. Select CONFIGURE and confirm.
6. Select FACTOR and confirm.
7. Enter the calculated factor and confirm.
8. Go back to the MAIN MENU or the Measurement mode display.
Example for engine oil Example for naphthalene