Do Calibration - Hanna Instruments HI2400 Instruction Manual

Calibrate the instrument frequently, especially if high accuracy is required.
The instrument can be calibrated in maximum 2 points: 0.0% (zero
calibration) and 100.0% (slope calibration).
The zero calibration of the HI2400 is very stable, therefore this procedure
needs to be performed only whenever the probe or the membrane is
replaced.
However, because the slope calibration is more critical, it is recommended
to perform this procedure every week.
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
switch.
• 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 15). Make sure the
salinity factor is set to zero (see page 16).
ZERO CALIBRATION
• Submerse the probe into HI7040 zero oxygen
solution and stir gently for 2‑3 minutes.
• Press CAL. The "~" and " " tags will blink on
the LCD until the reading is stable.
• When the reading is stable, "CFM" starts
blinking. Press CFM to confirm the "0.0%" DO
calibration.
• If the reading is within the limits (±15% f.s.),
the meter stores the value (and adjusts the slope
point).

DO CALIBRATION

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HI7040