Lufft WS501-UMB User Manual

Operating Manual Compact Weather Station
G. Lufft Mess- und Regeltechnik GmbH, Fellbach, Germany 9
4 Equipment Description
The WS family is a range of low cost, compact weather stations for the acquisition of a
variety of measurement variables, as used for example for environmental data logging in
road traffic management systems. Depending on the model, each device has a different
combination of sensors for the various measurement variables.
WS200-
UMB
WS300-
UMB
WS301-
UMB
WS400-
UMB
WS500-
UMB
WS501-
UMB
WS600-
UMB
Air temperature
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Humidity
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Air pressure
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Precipitation
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Wind direction
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Wind speed
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Compass
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Global Radiation
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Attention: Please note that, due to the approval of the radar sensor used, there are different
country options on equipment which includes precipitation measurement.
The equipment is connected by way of an 8 pole screw connector and associated
connection cable (length 10m).
The measured values are requested over the RS485 interface in accordance with UMB
protocol.
During commissioning, configuration and measurement polling takes place using the UMB-
Config-Tool (Windows
®
PC software).
4.1 Air Temperature and Humidity
Temperature is measured by way of a highly accurate NTC-resistor while humidity is
measured using a capacitive humidity sensor. In order to keep the effects of external
influences (e.g. solar radiation) as low as possible, these sensors are located in a ventilated
housing with radiation protection. In contrast to conventional non-ventilated sensors, this
allows significantly more accurate measurement during high radiation conditions.
Additional variables such as dewpoint, absolute humidity and mixing ratio are calculated
from air temperature and relative humidity, taking account of air pressure.
4.2 Air Pressure
Absolute air pressure is measured by way of a built-in sensor (MEMS). The relative air
pressure referenced to sea level is calculated using the barometric formula with the aid of
the local altitude, which is user-configurable on the equipment.
4.3 Precipitation
Tried and tested radar technology from the R2S-UMB sensor is used to measure
precipitation. The precipitation sensor works with a 24GHz Doppler radar, which measures
the drop speed and calculates precipitation quantity and type by correlating drop size and
speed.
4.4 Wet Bulb Temperature
The wet bulb temperature is the temperature resulting between a wetted or iced surface at a
flowing air.
4.5 Specific Enthalpy
Parameter of state of the humid air, composed of the specific enthalpies (heat capacity) of
the components of the mixture and related to the mass fraction of the dry air (at 0°C).

Lufft WS501-UMB Specifications

General

Brand	Lufft
Model	WS501-UMB
Category	Weather Station
Language	English