Operational Guide
71
DO
Calibration
When the reading is stable and is within the limits,
“CFM” tag starts blinking. Press CFM to conrm the
100.0 % DO calibration.
Press CAL to leave calibration after the rst point. The instrument will display
“SAVING” message and it will return to measurement mode memorizing the
slope calibration data.
Zero Calibration
Press CAL or continue with calibration after
conrming rst point.. The meter will display “WAIT”
and “0.0 %” will be displayed in lower right corner.
Submerse the probe membrane and temperature
sensor into the beaker containing HI 7040 Zero
Oxygen solution and stir gently for 2-3 minutes. The
reading will go down.
When the reading is stable and stops decreasing,
“CFM” tag starts blinking. Press CFM to conrm the
0.0 % DO calibration.
The instrument will display “SAVING” message and
it will return to measurement mode. Rinse probe tip
o in water before taking measurements in samples.