Ultrasonic Wind Speed and Direction Smart Sensor (S-WCG-M003) Manual
1-800-LOGGERS 6
www.onsetcomp.com
4.
Use the alignment tool to align the sensor so it is pointing
north.
5.
Once the sensor is aligned to north, tighten the screws and
remove the alignment tool.
Maintenance
The sensor does not normally require any maintenance other
than an occasional cleaning. Use a clean soft cloth with mild
soap and fresh water. Do not use alcohol-based cleaning
products.
Connecting the Sensor to a Station
To connect the sensor to a station, stop the station from
logging and insert the smart sensor’s modular jack into an
available smart sensor port on the station. See the station
manual for details on operating stations with smart sensors.
Measurement Operation
Wind direction measurements are averaged over the logging
interval or a 3-second timeframe (whichever is greater). If you
set up the sensor to log faster than every 3 seconds, the same
sensor reading will be recorded until a new 3-second average is
calculated. For example, if the sensor is logging at a 1-second
interval, the sensor will report the same wind direction (its
calculated average) for three samples before calculating and
reporting a new value for another three samples. Measurement
averaging for this sensor is independent of the logger’s
measurement averaging. Therefore the automatic
measurement averaging for this sensor is not affected by any
sampling intervals entered for averaging on other sensors.
Direction
Averaging
Unit vector averaging is used to determine wind direction
because traditional averaging would produce inaccurate
results. For example, three measurements of 350, 11, and 12
degrees—which are all winds from the north—averaged
together would result in 126 degrees, which incorrectly
indicates a southeasterly wind. Instead, the vector components
(North/South and East/West) for each wind measurement are
calculated every three seconds for the duration of the logging
interval. At the conclusion of the logging interval, the
North/South and East/West components are averaged and
then re-combined to calculate the average wind direction for
the logging interval.
Verifying Sensor Accuracy
It is recommended that you check the accuracy of the sensor
annually. The sensor cannot be calibrated. If the smart sensor is
not providing accurate data, then it is damaged.
Replacing the Battery
The sensor uses a LIFEPO4 3.2 V – 600 battery (HRB-WCG) to
charge the built-in solar panel on the top of the sensor. If
HOBOware® or HOBOlink® is consistently reporting wind speed
and gust speed readings of zero and wind direction at 178.3
degrees in error, then the battery likely needs to be replaced.
To replace the battery:
1.
Remove the sensor from the mounting location.
2.
Remove the cap from the bottom of the sensor rod and
disconnect the battery cables.
3.
Mark the underside of the sensor head where the north
alignment marking is located for easier reattachment later.
4.
Using a Phillips-head screwdriver, unscrew the three
sensors (two of which are shown in the previous photo) to
detach the sensor head from the tube.
5.
Slide the sensor rod away from the sensor top and gently
pull the battery and its cables completely out of the sensor
tube.
Mark the
sensor head
where the
north marking
is located
Disconnect the battery
cables
Cap removed
from sensor
rod
Remove the battery
and the battery cables
from the sensor rod