5
OXY 7
3. Calibration of the oxygen sensor
The polarographic sensor is an active sensor that changes its response with wear and aging, so you need
to calibrate it regularly in the air.
3.1 Calibration in air at 100%
The ordinary calibration is made at 100% in air.
Turn the instrument on, place the probe in the water and wait for the polarization time of 10 minutes. At
the end of 10 minutes, dry thoroughly the probe with a paper towel and proceed as follows:
1) Place the probe in the air with the membrane downwards and wait 2 minutes.
2) Press
to start the calibration process, the upper display will flash "CAL" and the lower right
corner shows "
100
".
3) When the reading is stable and appears
icon, press
button to confirm, the display
shows
End
and the meter enters measurement mode.
The oximeter is calibrated and is ready for use.
3.2 Calibration with zero oxygen standard
Normally it is sufficient to calibrate the instrument in air at 100%, as explained previously. However in
some cases it may also be necessary to calibrate at 0%, for example when:
You change the probe with a new one
The probe is not used for long period (over one month)
A complete maintenance of the sensor is performed
The instrument does not calibrate at 100%, in which case calibrate before at 0%
The instrument does not measure correctly
For the calibration at 0% proceed as follows:
Before proceeding, make a
Maintenance of the probe DO7/3mt
.
Turn the instrument on, place the probe in the water and wait for the polarization time of 10 minutes. At
the end of 10 minutes, dry thoroughly the probe with a paper towel and proceed as follows:
1) Put the probe in the zero standard oxygen and wait 5 minutes.
2) Go to the parameter
P5.1
of the setup menu, press the
key to start the calibration process,
the upper display will flash "
CAL
" and the lower right corner shows "
0
", gently shake the probe in
the standard.
