Users Manual

Operating Manual Smart Weather Sensor
G. Lufft Mess- und Regeltechnik GmbH, Fellbach, Germany 13
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.
Note: Devices with precipitation radar are subject to approval regulations which differ
between countries. Please make sure to observe chapter 1.3!
WS401-UMB and WS601-UMB are using an unheated rain gauge for precipitation
measurement. This version can be recommended for low power application etc.
4.4 Wet Bulb Temperature
The wet bulb temperature is the temperature of a moist or icy surface exposed to air flow.
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).
4.6 Air Density
The air density indicates how much mass in a given volume of air is contained and it is
calculated from the measured values of air temperature, humidity and air pressure.
4.7 Wind
The wind meter uses 4 ultrasonic sensors which take cyclical measurements in all directions.
The resulting wind speed and direction are calculated from the measured run-time sound
differential. The sensor delivers a quality output signal indicating how many good readings
were taken during the measurement interval.
4.8 Compass
The integrated electronic compass can be used to check the north – south adjustment of the
sensor housing for wind direction measurement. It is also used to calculate the compass
corrected wind direction.
4.9 Heating
The precipitation sensor and wind meter are heated for operation in winter.
4.10 Global Radiation
The global radiation is measured by a pyranometer mounted in the top cover of the Smart
Weather Sensor.
4.11 Lightning Sensor
WS800-UMB includes lightning detection by an integrated sensor analysing the radio wave
emission of lightnings. It delivers a count of recognized lightnings.
The sensor analyses spectrum and wave form of the received signal to suppress the
detection of man made electrical discharges. Nevertheless false detections can not be totally
excluded specially in an environment with high power electrical equipment.
4.12 External Temperature Sensor
Optionally all models may be equipped with an external NTC temperature sensor for the
acquisition from additional measurement points. The type of NTC is the same as used for the
internal air temperature sensor.
External temperature sensor and external rain gauge can not be connected at the same
time.