Ambient Pressure During Dissolved Oxygen Measurement; Conductivity; Measuring Ranges And Cell Constants; Calibration Of The Conductivity Electrode - Tintometer Lovibond SD 335 Multi Mode D'emploi

6 .6 Ambient pressure during dissolved oxygen measurement

The air pressure ratios at the place of measurement play a major role in:
• The calculation of the O
• The calculation of the O
• The evaluation of the calibration
An integrated air pressure sensor is used to continuously measure the ambient pressure and
compensate it for the calculation.

7 Conductivity

7 .1 Measuring ranges and cell constants

Depending on the type of electrode, different measuring ranges are accessible depending on
the cell constant K. The cell constant of the measuring cell must be entered in the parameter
configuration for conductivity before use. Information regarding factory-tested cell constants
can be found in the test log or on the cable tag on the electrode.
Conductivity measuring
cell
LC 12
LC 16
Alternatively, the cell constant can be determined via calibration either using the automatic
recognition of a standard reference solution or the manual entry of a known conduction value.

7 .2 Calibration of the conductivity electrode

If used correctly, the standard electrodes remain stable over time. Using the integrated cali-
bration function, the original cell constant can be checked for changes. The cell constant
may differ, for example due to contamination on or damage to the surface of the original cell
constant. Alignment of the cell constant clarifies the current state of the measuring cell and
contributes to the assessment of whether it needs to be cleaned or replaced. Please set the USB
mode to mass storage in the instrument configuration before calibration. Proceed as follows:
Con
µS/cm
SD_335_1 10/2020
saturation (% O
2
concentration (ppm, mg/litre)
2
Cell constant
ca. 0,55 cm
ca. 0.42 cm
Prepare a reference solution with a known conductivity.
Rinse the electrode first with distilled or deionised water and then
with the reference solution.
Immerse the electrode in the reference solution. Ensure that there are
no air bubbles on the electrode surface and that the electrode including
temperature sensor is sufficiently surrounded by the reference solution.
)
2
-1
-1
Measuring range
< 200 mS/cm
< 1000 mS/cm
55