DAVIS WeatherLink for Alarm Output Add. User Manual

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For guidance on how to use this alarm, it may be best to consult histori-
cal weather data from WeatherLink plot data (or other sources) to deter-
mine what kind of behavior a parameter exhibits before approaching a
value of concern. Make note of how quickly the value changes over
time before it reaches that value. These changes will govern your
threshold values and time period. Your second threshold probably
should not match this value, but rather be lower than this value for a
upward trend alarm and higher than this value for a downward trend
alarm.

• = (Equal) can be used to check whether any value is exactly equal to the

set threshold value entered.

• Minus or “difference” alarm allows you to compare the difference

between two like variables. For this check type, the two variables must
be measured in the same units of measure. If this check type is selected,
the software will use the parameter pick list on the row below for the
second of the two like variables. Then enter the difference (as a positive
number) you want to compare. Select whether you want to check a