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HYSTERESIS
To compensate for fluctuation of the weather data, which may cause the weather alarm to ring
constantly if the measured reading is close to the alarm level, a
hysteresis function has been implemented for each weather
alarm.
For example, if the high temperature alarm is set to 77°F and
the temperature reaches 77°F, the alarm will be activated. If the
temperature then drops to 76.8°F (a change of less than 1.8°F)
and then increases to 77°F again, the data will blink, but no
alarm will be activated.
The temperature would have to drop below 75.2°F (with a pre-
set hysteresis of 1.8°F) so that the alarm can be produced again.
Hysteresis values for the various weather data types are given in
the table.
Note: The temperature or humidity data will keep flashing even after a weather alarm has
been switched off by a key press. The flashing value indicates that the current weather
condition is out of the pre-set weather alarm limit(s).
WEATHER FORECAST AND WEATHER TENDENCY
WEATHER FORECASTING ICONS:
Sunny
Cloudy with sunny intervals
Rainy
For every sudden or significant change in the air pressure, the weather icons will update
accordingly to represent the change in weather.
Every time a new average pressure value has been obtained (once per minute), this value is
compared with an internal reference value. If the difference between these values is bigger
than the selected weather tendency sensitivity, the weather-icon changes, either for worse or
for better. In this case, the current pressure value becomes the new weather tendency
reference.
If the icons do not change, either the air pressure has not changed or the change has been too
small for the Weather Center to register. You may adjust the "sensitivity" of the pressure
change check in the setting mode –see WEATHER TENDENCY SENSITIVITY VALUE SETTING
above.
Weather data
Hysteresis
Temperature
1.8°F
Humidity
3% RH
Pressure
0.029 inHg
Wind speed
6.2 mph