User Guide

TURNING THE METER ON

To switch the meter on, press the ON/OFF switch key

and leave the probe in the auto-conditioning (polar-

ization) mode before proceeding. After approximately

5 minutes, the instrument can be calibrated (see

page 12).

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 measurements with the same recur-

ring degree of accuracy.

With the probe properly polarized, oxygen is continually “consumed” when it

passes through the sensitive diaphragm and dissolves in the electrolyte solu-

tion contained in the probe.

If polarization is interrupted, the electrolyte solution continues to be enriched

with oxygen 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 9), i.e. the membrane cap is filled with electrolyte

and the probe is connected to the meter and properly polarized.

For an accurate calibration, it is recommended to wait at least 15 minutes to

ensure precise conditioning of the probe.

Keep the protective cap on during the polarization time and remove it for the

calibration and the measurements.

Follow the calibration procedure on page 12.

The Platinum cathode (#8 in the Functional Descripti on page 4)

should always be bright and untarnished. If it is tarnished or stained,

the cathode should be cleaned. You can use a clean lint-free cardboard

or cloth. Rub the cathode very gently side to side 4-5 times. This will

be enough to polish and remove any stains without damaging the

platinum tip. Afterwards, rinse the probe with deionized or distilled

water and install a new membrane cap using fresh electrolyte and

follow the steps above. Re-calibrate the instrument.

Important

In order to have accurate and stable measurements, it is important

that the surface of the membrane is in perfect condition. This semiper-

meable membrane isolates the sensor elements from the environment

but allows oxygen to enter. If any dirt is observed on the membrane,

rinse carefully with distilled or deionized water. If any imperfections still

exist, or any damage is evident (such as wrinkles or tears-holes), the

membrane should be replaced.

Make sure that the O-Ring sits properly in the membrane cap.