User Guide

9
TURNING THE METER ON
To switch the meter on, press
the ON key and let the probe
in the auto-conditioning (po-
larization) mode before pro-
ceeding. After approximately
5 minutes, the instrument can
be calibrated (see page 17).
If the probe is disconnected,
the meter will display "----".
This also indicates the possibility of a broken
probe cable.
PROBE POLARIZATION
The probe is under polarization with a fixed
voltage of approximately 800 mV.
Probe polarization is essential for stable mea-
surements with the same recurring degree of
accuracy.
With the probe properly polarized, oxygen is
continually "consumed" when it passes
through the sensitive diaphragm and dissolves
in the electrolyte solution contained in the
probe.
If polarization is interrupted, the electrolyte
solution continues to be enriched with oxy-
gen until it reaches an equilibrium with the
surrounding solution.
Whenever measurements are taken with a
non-polarized probe, the oxygen level revealed
is both that of the tested solution as well as
that present in the electrolyte solution. This
reading is incorrect.
The calibration of this instrument is very
simple.
Before proceeding with the calibration make
sure the probe is ready for measurements
(see page 8), i.e. the membrane cap is filled
with electrolyte and the probe is connected
ON
ppm
°C