La Crosse Technology WS-2811U-IT - Manual (Page 23)

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AIR PRESSURE HISTORY GRAPH
The LCD shows the relative air pressure value and the air pressure history on a bar graph.
Press the SET key to toggle between Mode1 and Mode2 of the display.
Mode 1: The bar graph displays the air pressure history of the past 24 hours in seven
steps. The horizontal axis represents the last 24 hours of air pressure recording (-24, -18,
-12, -8, -6, -3 and 0 hour).
Mode 2: The bar graph displays the air pressure history of the past 72 hours in seven
steps. The horizontal axis represents the last 72 hours of air pressure recording (-72, -48,
-36, -24, -12, -6 and 0 hour).
The vertical bars are plotted at each of the seven steps and give the trend over the recorded
period. The 0 hour vertical bar will always display at the midline height to indicate the current
air pressure. The varying height of bars in other columns on the graph indicate a relative change
in air pressure up or down from the previous measurement.
New pressure measurements are compared to previously recorded pressure measurements.
The pressure change is expressed by the difference between the current ("0h") and the past
readings in divisions of ±0.06 inHg or ±2 hPa. If the bars are rising from left to right, this
indicates that the weather is getting better due to an increase in air pressure. If the bars are
falling from left to right, this indicates that the weather is expected to get worse due to a drop
in air pressure.
At every full hour, the current air pressure is used as a basis for the display of a new graph bar.
The existing graph is then moved one column to the left.
Note: For accurate barometric pressure trend, the Weather Center should operate at the
same altitude. Should the unit be moved, for instance from the ground to the second floor of
the house, the readings for the next 48-60 hours shall be discarded.
Note: The bar graph will scroll right to left regularly to prevent LCD burnout.
WIND DIRECTION AND WIND SPEED MEASUREMENT

A pointer on the outer circle of the compass indicates the current wind direction.

The last 6 wind directions are displayed with pointers on the inner circle.

The wind direction (abbreviation or degrees) is displayed in center of compass.
Press the SET key to toggle between Mode1 and Mode 2 of the display.
Mode 1 displays the following wind data:

Wind direction

Wind chill in

F or

C

Wind speed in mph, km/h, bft, knots or m/s