JUMO AQUIS 500 RS, Operating Manual, Page: 72 / 120

8 Calibrating sensors
72
Start end value calibration
✱
Wait until the displayed value has stabilized.
✱
Start calibration using the key.
The "ENTRY REFERENCE" display flashes and shows the last determined
oxygen saturation value
NOTE
Water-vapor-saturated air occurs, for example, directly above the surface in a
half-full sample vessel of tap water.
To achieve successful calibration, the following points must be taken into
account:
• Both the sample vessel and the water must be clean.
• The water should be left to stand in the sample vessel for at least 30 min-
utes before calibration, so that an equilibrium is established in the gas
exchange between water and ambient air.
• Ideally, a holder should be installed to mount the sensor above the water
surface.
• The sensor must be kept dry during the calibration process. Drops of water
adhering to the sensor membrane could distort the measurement result.
• The air pressure and, above all, the temperature must remain constant
during the calibration.
• Direct sunlight and drafts in the immediate vicinity of the sample vessel
should be avoided.
• Wait a few minutes until the measured temperature stops changing. In the
event of larger temperature differences between water and air, this can
take up to 30 minutes.