Orion Car Audio 420 - Manual (Page 14)

14 Orion 420 Weather Station
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Columbia Weather Systems, Inc.
direction reported indicates the direction that the wind comes from. North
is represented as 0°, east as 90°, south as 180°, and west as 270°.
The wind direction is not calculated when the wind speed drops below
0.05 m/s. In this case, the last calculated direction output remains until
the wind speed increases again to the level of 0.05 m/s.
The average values of wind speed and direction are calculated as a
scalar average of all samples over the selected averaging time (1 ... 900
s). The sample count is based on a 4 Hz sampling rate. The minimum
and maximum values of wind speed and direction represent the
corresponding extremes during the averaging time.
Pressure, Temperature, and Relative Humidity (PTU)
Module
Barometric pressure, temperature, and humidity measurements are
combined in an advanced sensor module (PTU) utilizing a capacitive
measurement method for each parameter. The PTU module contains
separate sensors for pressure, temperature, and humidity measurement.
The measurement principle of the pressure, temperature, and humidity
sensors is based on an advanced RC oscillator and two reference
capacitors against which the capacitance of the sensors is continuously
measured. The microprocessor of the transmitter performs compensation
for the temperature dependency of the pressure and humidity sensors.
Barometric pressure is measured using a capacitive silicon
BAROCAP® sensor. The sensor has minimal hysteresis and excellent
repeatability, as well as outstanding temperature and long-term stability.
Temperature is measured with a capacitive ceramic THERMOCAP®
sensor.
Relative humidity measurement is based on a capacitive thin film
polymer HUMICAP®180 sensor. The sensor is highly accurate with
negligible hysteresis and excellent long-term stability in a wide range of
environments.
Radiation Shield: This module is mounted in a specially-designed
radiation shield which protects the sensors from both scattered and
direct sunlight and precipitation. The composite material in the plates
offers excellent thermal characteristics and UV stabilized construction.
The white outer surface reflects radiation, while the black inside absorbs
accumulated heat.
The internal sensor module is easily replaceable and readily available as
a spare component. To order a replacement module, please use catalog
no. 9581.