®
PS-3209
Wireless Weather Sensor
5
013-15518A
Consider using the PS-3553 Weather Vane Accessory
when measuring weather conditions including wind
speed and direction.
Measurement Tips
Equilibration Time
After a rapid change in temperature or humidity, the
sensor may take several seconds to come to equilibrium
with the environment. Observe the measurements and
wait for them to stabilize.
Alignment with Wind
Hold the sensor so that wind blows straight into the front
of the anemometer.
Shade
The sensor, especially the temperature and humidity
transducers, must be out of direct sunlight to make
accurate measurements.
Moisture
Protect the sensor from liquid water. The sensor is rug
-
ged and weather-resistant, but not waterproof.
Wireless Weather Sensor
Primary Measurements
The primary measurements are wind speed,
temperature, relative humidity, and barometric pressure.
Wind Speed
The sensor determines Wind Speed from the rate of
rotation of the anemometer (wind turbine). It assumes
that air is flowing straight into the turbine. Wind speed
must be at least 0.5 m/s to be measured accurately.
Wind speed is measured in units of m/s, cm/s, mm/min,
km/h, mph (miles per hour), knots, and ft/s (feet per
second).
CAUTION: Do not try to measure high-speed wind such
as from leaf-blowers or severe storms.
Temperature
Temperature is measured by the thermistor temperature
transducer. To work accurately, the transducer must be
in shade. Temperature is measured on the Celsius,
Fahrenheit, and Kelvin scales.
Relative Humidity
Relative humidity is measured by the humidity
transducer. To work accurately, the transducer must be
in shade and at air temperature. Relative humidity is
reported as a percentage representing the ratio of the
partial pressure of water vapor to the saturated vapor
pressure. Relative humidity is reported as “%”.
Barometric Pressure
Barometric Pressure is measured by a pressure
transducer in the sensor’s “window”. The reported
Barometric Pressure is the actual air pressure, not
sea-level corrected pressure. Barometric Pressure is
measured in units of kPa (default), psi, N/m
2
, atm, torr,
hPa, inHg, mmHg, mbar, Pa, and inH
2
O
Secondary Measurements
Each secondary measurement is a calculation based on
one or more of the primary measurements.
Absolute Humidity
Absolute Humidity (or water vapor density) is a measure
of the mass of water vapor present in a given volume. It
Wireless Weather Sensor and Weather Vane Accessory
