Hanna Instruments Edge, Instruction Manual

Page: 70 / 96

Operational Guide 70
When water is fresh containing no sea water, the concentration of oxygen will
be at a maximum. The solubility of the oxygen dissolved in water is decreased
when water is brackish or seawater. The solubility of oxygen in water is
decreased when measurements are made at elevations above sea level.
Before proceeding with the calibration, make sure the probe is ready for
measurements (see page 65), i.e. the membrane cap is filled with electrolyte,
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
conditioning of the probe. Keep the protective cap on during polarization
time and remove it for calibration and measurements. Follow the calibration
procedure. Calibrate the probe frequently, especially if high accuracy is
required. The probe can be calibrated at 2 points: 100.0 % (slope calibration)
and 0.0 % (zero calibration).
Initial Preparation
Prepare a fresh bottle of HI 7040 by following package directions. Use
solution within one month of preparation. Pour small quantities of HI 7040
Zero Oxygen solution into a beaker.
Remove the protective cap if used.
100% Saturated Calibration
It is suggested to perform the slope calibration in water/saturated air.
Pour a small beaker of water.
Rinse the polarized probe with clean water.
Dry the probe tip and allow a few seconds for the LCD reading to stabilize
(probe in air).
Suspend over beaker of water.
Press CAL.
The “ ” tag will be displayed along with “WAIT”
blinking on the LCD until the reading is stable.
DO
Calibration
DO Meter
Configuration