General Tools and Instruments DAF4000 - Manual (Page 10)

6. Mode for measuring the instant wind speed with electronic compass DAF3300, DAF4000
Choice of the unit of measurement (wind) :
See section 3, choice of the unit of measurement.
Compass display :
The compass display is given in degrees on the small digits.
WHICH MEANS ! Your GENERAL ® Mini Airflow tells you magnetic north, and
not geographical north !
Measurement :
To carry out a measurement as accurate as possible, hold your instrument perfectly vertical (fig. A). If the figures are replaced
by
, that means that the instrument is too tilted or that it is being disturbed by a nearby magnetic source.
fig. A
Calibration :
IMPORTANT ! Calibrate your Mini Airflow before the first use and at each change of environment or battery.
When the instrument is first energised, the compass shows . So you carry out a calibration as follows :
Hold the button pressed down for approximately 3 seconds, and when appears in the large digits, release. Then turn
yourself round until the instrument is showing , then, in order to validate the calibration, press briefly on the button.
During the calibration, the instrument shows in succession , , then and finally in front of the small digits.
This operation needs to take place at the speed of 1 turn in approximately 30 seconds.
To obtain an accurate calibration, the impeller MUST NOT turn ! If there is wind, shelter the impeller between your thumb
and your index finger.
Note : The lines of a terrestrial magnetic field are disturbed by metal environments, buildings, electricity pylons, vehicle
interiors, metal boats and also by magnetic fields generated by any electrical machinery or equipment and by magnets. It is
therefore necessary, in order to obtain accurate measurements, to move away from the sources of disturbance, or to
recalibrate.
ILJ $
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