17
Choice of Pressure Measurement Unit:
The air pressure can be shown in inHg (inches of Mercury) and hPa (hectoPascals/millibars) . To change
the units press and hold the button for approximately 4 seconds and the units will change . Release the
button when the desired units are displayed and the instrument returns to the mode of measuring the
instant wind speed with display of the air pressure . This setting will remain until changed again, even
after turning the Xplorer 4 off .
Display of absolute pressure (QFE):
Keep the button pressed down for approximately 2 seconds and at the very moment
when the indication (QFE) is displayed in the large digits, release it . The instrument then
goes into the mode for displaying absolute pressure . To quit this mode, press once on the
button, and the instrument returns to the mode wind speed and QNH/relative pressure .
Calibration of relative pressure (QNH):
Before using the Xplorer to measure relative air pressure, be sure to calibrate it to
a known relative air pressure reading . Alternatively, it can be calibrated to a known
altitude, please see the previous section on altitude . While in the air pressure mode,
press and hold the button for 3 seconds until appears in the large digits and release .
Press and hold the button to increase the
air pressure in steps of 0 .01 inHg or 1
hPa. To reduce the air pressure, release the button briefly then once again press and hold
the button . As the button is held, the air pressure will increase/decrease at a faster rate .
If the air pressure requires a large change and the button is held down for many seconds, the Xplorer
4 may start to flash to turn off. Simply release the button, then repeat to adjust. Once the air pressure
reading is correct, release the button, then briefly press it once.
Comments:
If QNH figure is steady (is not flashing) this indicates the current relative pressure (QNH) credible
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due to a slow change, indicative of a change in weather patterns, not altitude change .
The QNH sign flashes if this pressure has changed since the last calibration.
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If the QNH figure is flashing, it indicates the QNH pressure entered at the last calibration.
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A rise in altitude or a meteorological variation when the recording is not active makes the QNH
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figure flash.
