5.5 Thermistor
A small stainless steel needle containing a thermistor extends from the middle of the four sonic
transducers in the center of the anemometer. The thermistor sits in open air. Instead of using a
radiation shield to prevent solar loading, the temperature measurement is corrected by an energy
balance equation that uses solar radiation and wind speed measurements. The equation
calculates the true air temperature based on the solar load on the needle and the convective
cooling of the thermistor to an accuracy of ±0.6 °C. Compare this error to the combined
temperature and radiation shield errors of competitive units. For more information, refer to the
ClimaVUE™50—Correction of air temperature measurements from a radiation-exposed sensor
White Paper available at: www.campbellsci.com/app-notes.
5.6 Tilt sensor
After initial leveling with a small level or the built-in bubble level, the internal tilt sensor helps
users keep the ClimaVUE 50 level. Regularly check the X and Y tilt data. Adjust the ClimaVUE 50
leveling if it has tilted. More than two degrees off level can cause errors in the rain and solar
radiation measurements. Although this tilt sensor may be used to level the instrument, it is much
easier to use the small bubble level on the bottom of the anemometer plate.
The tilt sensor is an accelerometer that reads whatever acceleration it is experiencing. Under
static conditions, this is the gravitational acceleration, and therefore provides an accurate
indication of tilt. However, if the sensor is not securely mounted, the tilt sensor measures a
combination of gravity and vibration.
5.7 Barometric pressure sensor
The barometric pressure sensor is located behind the Teflon screen next to the relative humidity
sensor on the same circuit board. It measures the atmospheric pressure in the range of 500 to
1100 hPa.
5.8 Lightning sensor
The lightning sensor uses AM radio signals, which are disrupted by lightning. Circuitry inside the
sensor detects disrupted AM signal. The ClimaVUE 50 records the time of the disruption and
determines strike distance based on the intensity of the signal.
ClimaVUE 50 Compact Digital Weather Sensor 9
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