13
INITIAL PREPARATION
• Pour small quantities of
HI7040
Zero Oxygen solution into a beaker.
If possible, use a plastic beaker to minimize any EMC interferences.
• Make sure the probe is ready for measurements (see probe preparation
on 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/Off
key.
• For an accurate calibration, it is recommended to wait for at least
15 minutes to ensure precise conditioning of the probe.
• Remove the protective cap from the DO probe.
• Set the appropriate altitude factor (see
page 19). Make sure the salinity factor is
set to zero (see page 18).
ZERO CALIBRATION
• Submerge the probe into
HI7040
zero oxygen solution and stir gently
for 2-3 minutes.
• Press
CAL
. The “ ” and “
NOT READY
”
tags will blink on the LCD until the
reading is stable.
• When the reading is stable, and is within
the limits (±15% f.s.) “
CFM
” starts
blinking. Press
CFM
to confirm the
“
0.0%
” DO calibration.
• Press
CAL
. The instrument will return to measurement mode and will
memorize the zero calibration data. For a
two-point calibration do not press
CAL
and
follow the procedure below.
