La Crosse Technology Family Weather Station Instruction Manual page 29

2. Press and hold the SET key for about 2 seconds. The wind speed digit will
start flashing. Press the + or MIN/MAX key to set the high wind speed alarm
value.
3. Press the ALARM key to confirm the setting. The digit will stop flashing. Press
the SET key to switch on or off the alarm. (The showing of the icon ((( )))
means that the alarm is switched on.)
4. Press the ALARM key once to return to the normal display mode.
In case the wind speed exceeds the condition for high wind speed alarm, the value
will be flashing, along with the corresponding high alarm icon ("HI AL"). And the
buzzer will ring for 2 minutes. User may press any key to stop the sound.
HYSTERESIS
To compensate for fluctuation of the measured data, which may cause the weather
alarm to sound constantly if the measured reading is close to your set level, a
hysteresis function has been implemented for each weather alarm. For example, if the
high temperature alarm is set to +25°C and the current value moves to +25°C, the
alarm will be activated (if it has been enabled). Now when the temperature drops to
+24.9°C or below and thereafter again increases to beyond +25°C, the data will be
blinking, but no alarm will be activated. It has to drop to below +24°C (with a pre-set
hysteresis of 1°C) so that the alarm can be produced again. Hysteresis values for the
various weather data types are given in the following table:
Weather data
Temperature
Humidity
Wind speed
Hysteresis
1°C
3% RH
5 km/h
29