DAVIS GroWeather Console User Manual
Page 22
Alarms
GroWeather Manual
Page 15
The three special alarms are described below:
• ETo
ETo is updated only once an hour, on the hour. If during a given hour the
ETo value exceeds the alarm threshold, that information causes the ETo
alarm to sound
at the end of that hour
. This is true for both the “daily” and
Total ETo alarms.
In addition, for the “daily” alarm, the GroWeather automatically sub-
tracts the ETo alarm threshold value from the “daily” ETo amount after
the alarm is triggered. (This subtraction effectively clears “daily” ETo
once the alarm is triggered.) Thus, if you are using the “daily” ETo alarm
(at any threshold), do
not
use the ETo AutoClear feature because: (1)
there is no need, the value resets automatically, and (2) setting the ETo
AutoClear may interfere with triggering the alarm at the appropriate
time.
A new feature in the GroWeather allows you to set the station to gener-
ate a signal for every hundredth-inch of ETo. For example, if in an hour,
three-hundredths of an inch ETo is returned to the air, at the end of the
hour 3 discrete signals will be generated by the station. For this applica-
tion, set the alarm threshold to 0.01”, and attach an Alarm Output Mod-
ule (AOM) to receive the signal. Any other threshold (other than 0.01”)
will cause the alarm to function as normal (giving just one signal at the
end of the hour when the alarm threshold is exceeded).
Note:
In order for the alternative (0.01”) setting to work, you must have an AOM connected to
your system, otherwise the ETo alarm will sound continuously. Also, make sure you set the
alarm threshold in inches (even if you are displaying total ETo in millimeters).
• Barometric Pressure
The barometric pressure alarm alerts you to changes in barometric pres-
sure. You may select a rate of change per hour (0.2”/0.4”/0.6”, 0.5 mm/
1.0 mm/1.5 mm, 0.7 hPa/1.4 hPa/2.0 hPa) and the GroWeather’s alarm
will sound if the rate of change (in either direction) exceeds your thresh-
old.
• Dew-Point
The Dew-Point alarm alerts you when the temperature comes within 2˚F
(1˚C) of the dew-point.
• Time
The time alarm is a standard “alarm clock” type of alarm. It will sound
for one minute.