Calibration procedure – Hanna Instruments HI 96821 User Manual

Page 7

CALIBRATION PROCEDURE

Calibration should be performed daily, before measurements are made, when the battery has
been replaced, or between a long series of measurements.
1. Press the ON/OFF key, then release. Two instrument test screens will be displayed briefly;

all LCD segments followed by the percentage of remaining battery life. It will briefly display
an indication of the measurement units set. When the LCD displays dashes, the instrument is
ready.

2. Using a plastic pipette, fill the sample well with distilled or deionized water. Make sure the

prism is completely covered.

Note: If the ZERO sample is subject to intense light such as sunlight or another strong source,

cover the sample well with your hand or other shade during the calibration.

3. Press the ZERO key. If no error messages appear, your unit is calibrated.

(For a description of ERROR MESSAGES see page 11).

Note: The 0.0 screen will remain until a sample is measured or the instrument is turned off.
4. Gently absorb the ZERO water standard with a soft tissue. Use care not

to scratch the prism surface. Dry the surface completely. The instrument
is ready for sample measurement.

Note: If instrument is turned off the calibration will not be lost.