Vaisala AWS310-SITE, Руководство по интеграции

Страница: 20 / 78

3. Sensors
3.1 Vaisala Embedded Road and Runway
Sensor DRS511
DRS511 measures surface temperature, subsurface temperature (6 cm / 2.36 in depth), and
water film thickness and the amount of de-icing chemical on the road and runway surface.
DRS511 detects snow and ice on the surface. The measurements make it possible to
determine the freezing temperature and the risk of ice formation.
DRS511 contains precision Pt100 sensor elements that use the 4
‑
lead method for
temperature measurements. The Pt100 sensor elements are critical in determining the risk of
slippery conditions. Based on the DRS511 temperature measurements, the weather station is
able to estimate the current sky condition (no rain, rain, cloudy, or clear).
Because conductivity disappears for monocrystalline ice (black ice), DRS511 has an
integrated black ice detector that measures the characteristic capacitance of the road or
runway surface. This measurement is used in offset calibration to detect if the road or
runway is dry.
The weather station uses the surface temperature reading provided by DRS511 and the
temperature and relative humidity readings provided by atmospheric sensors to recognize
the formation of frost on the road or runway. Frost may be formed when the surface
temperature is below freezing temperature and dewpoint or frost point.
In the weather station, DRS511 sensors are connected to DRI701. The weather station
supports up to 2 DRI701 cards, providing connections to a maximum of 4 DRS511 sensors.
DRS511 is installed in a hole that is chipped on a wheel track. The sensor is designed to wear
along with the road or runway surface, providing accurate readings of the surface state even
after a longer time.
More information
‣ Road Sensor Interface Card DRI701 (page 10)
‣
RWCC components for AWS310-SITE (page 12)
AWS310-SITE RWCC Integration Guide M212071EN-C
18