Hanna Instruments HI 9146 - Manual (Page 11)

11
For accurate Dissolved Oxygen measurements, a water movement of
0.3 m/s is required. This is to ensure that the oxygen-depleted
membrane surface is constantly replenished. A moving stream will
provide adequate circulation.
The use of a magnetic stirrer to ensure a certain fluid velocity is
recommended.
TEMPERATURE MEASUREMENTS
The probe has a built-in temperature sensor.
The measured temperature is indicated on the secondary LCD as shown
above.
Allow the probe to reach thermal equilibrium before taking any
measurement. This can take several minutes. The greater the difference
between the temperature at which the probe was stored and the
temperature of the sample, the longer the time will take to reach thermal
equilibrium.
Notes: • If “----” appears on the primary LCD and “NO Probe” is
displayed blinking, the DO probe is not properly connected or
the temperature is out of range. This also indicates the
posibility of a broken probe cable.
• If the temperature is out of range “ ºC” or “ºF” tag is
displayed blinking.
• If the reading is out of range, the full scale value will be
displayed blinking.
• If the reading is not stable, the stability indicator “ ” on.
• Make sure the meter is calibrated before taking measurements.
• If measurements are taken successively in different samples,
to have accurate readings it is recommended to rinse the
probe thoroughly with deionized water before immersion in
the samples.
• To maximize battery life, the meter is automatically switched
off after a set period of non-use. To reactivate the instrument
press the
On/Off key. This feature can be disabled (see
SETUP section for details).
BACKLIGHT FEATURE
The instrument is provided with a Backlight feature to
enhance display readability in low light conditions. It
can be easily toggled on and off through the keypad by
pressing
Light.
Note: The backlight automatically shuts off after a set time period to
save battery life (see SETUP for details, page 17).
If battery percentage is less than 20% the backlight can not be ON.