Graph Mode
Vantage Pro Console Manual
Page 27
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 Vantage Pro automatically subtracts
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 thresh-
old), 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 Vantage Pro allows you to set the station to generate 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 dis-
crete signals will be generated by the station. For this application, set the
alarm threshold to 0.01”, and attach an Alarm Output Module (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 Vantage Pro’s alarm
will sound if the rate of change (in either direction) exceeds your threshold.
• 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.
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