DAVIS WeatherLink Emergency Add. - Manual (Page 5)

Streaming Data Logger Functionality &
Troubleshooting
The ASCII character string that is sent every 30 seconds contains
information on the following parameters (as required by ALOHA
®
):
station ID #,
vector mean wind speed, (5 minutes average in meters per
second),
mean wind direction (5 minutes average in degrees true),
standard deviation of the wind direction (“sigma-theta”) (degrees),
mean air temperature, (5 minutes average in °C),
instantaneous wind speed (meters per second),
instantaneous wind direction (in degrees true),
instantaneous air temperature (°C),
instantaneous Vantage Pro™ console or Weather Envoy™ battery
voltage.
Upon powering up the console or interrupting communication for software
use, the streaming logger will not report the 5 minute average values until 5
minutes have elapsed. As specified by ALOHA
®
, the streaming logger will
place a -1 in the “sigma-theta” field until 5 minutes has elapsed and 5
minutes of data has been captured. ALOHA
®
will flag this data as a
communications problem, so be sure to let the Vantage Pro system run for
at least 5 minutes before utilizing the data in ALOHA
®
. Also, if data is
missing due to other problems such as disconnected sensors or poor
reception, average data may not be reported and a -1 may appear in the
“sigma-theta” field.
Additionally, if there is no wind speed over a 5 minute period, and thus no
real wind direction, the streaming logger will place a -1 in the “sigma-theta”
field. The -1 will also be indicated if the wind direction varies by 180
degrees or more over the 5 minute averaging period.
Please check your station and console if 5 minutes have elapsed and the
wind direction does not vary greatly (particularly if wind are not light), but
the streaming logger continues to report the -1 value, marks other data as
missing, or you get a communication error message in ALOHA
®
.
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