User Guide

17
D.O. CALIBRATION
For greatest accuracy, it is recommended
that the instrument is calibrated frequently.
The standard calibration program of the meter
is prepared for 2 (maximum) values: 0.0%
(zero calibration) and 100.0% (slope cali-
bration).
The meter is equipped with a stability indica-
tor and the user will be guided step by step
with easy indications on the display during
the D.O. calibration. This will make the cali-
bration a simple and error-free procedure.
The zero calibration of the HI964400 is very
stable, therefore this procedure needs only to
be performed whenever the probe or the
membrane is replaced.
However, because the slope calibration is
more critical, it is recommended to per-
form this procedure every week.
INITIAL PREPARATION
• Pour small quantities of
HI7040 Zero Oxygen solu-
tion into a beaker. If pos-
sible, use a plastic bea-
ker to minimize any EMC
interferences.
• Make sure the probe is ready for mea-
surements (see initial preparation at
page 8), i.e. the membrane is filled with
electrolyte and the probe is connected to
the meter.
• Switch the meter on by
pressing the ON key.
• For an accurate calibra-
tion, it is recommended
to wait for at least 15
H
I 7
0
4
0
HI 7040
ON