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WS501-UMB Smart Weather Sensor

Make:  Lufft                             Model: WS501 UMB
✅ Compact all-in-one weather sensor, low power, heater, aspirated radiation shield, maintenance-free operation, open communication protocol.
✅ Measurand : Temperature, Relative humidity, Air pressure, Wind direction, Wind speed, Solar radiation.
✅ Sensor Type : Compact weather station
✅ Signal output : RS485 with supported protocols UMB-Binary, UMB-ASCII, Modbus-RTU, ModbusASCII, XDR and SDI-12.
✅ Supplied With : 10 Meter standerd cable, Factory test/ Calibration certificate
✅ Article number : 8375.U01

From the WS product family of professional intelligent measurement transducers with digital interface for environmental applications. Integrated design with ventilated radiation protection for measuring: Air temperature, relative humidity, air pressure, wind direction, wind speed and radiation. One external temperature or rain sensor is connectable.

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. Air temperature values with reduced accuracy are available as service channels for additional information. Additional variables such as dewpoint, absolute humidity and mixing ratio are calculated from air temperature and relative humidity, taking account of air pressure.

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.

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.

Global Radiation: The global radiation is measured by a pyranometer mounted in the top cover of the Smart Weather Sensor.



✅ Weather observation for road and traffic control systems
✅ Automatic weather station / Automatic weather sensor (AWS)
✅ PV-Monitoring / Solar Monitoring on photovoltaic farms
✅ Hydro-meteorological stations
✅ Weather observation for building automation
✅ Weather stations at airports, marinas and onboard ships
✅ Integration into various other systems/solutions, where these measurement parameters are needed.
✅ Measuring wind direction and speed insusceptibly to bird nesting thanks to roofed construction
✅ All-in-one housing concept of a compact weather sensor combining several measurement parameters in one housing with only one cable connection
✅ Integrated Kipp & Zonen CMP3 Pyranometer
✅ Built-in data pre-processing, universal interfaces and selectable output protocols
✅ Compatible with many commercially available Met/HydroMet dataloggers and PLS systems thanks to an open communication protocol
✅ Maintenance-free operation – no moving parts that can wear out
✅ Suitable for all climate zones; also for solar-powered automatic meteorological stations
✅ Ventilated temperature and humidity measurement according to WMO guidelines.
✅ Integrated heater that can be switched on if there is danger of frost





Ø approx. 150 mm, height approx. 332 mm

Weight (Mass)

Approx. 1.5 kg


RS485, 2 – wire, half – duplex

Power Supply

11…32 VDC , 5…11 VDC (electronics with limited precision of measurements) , 24 VDC +/- 10% (heater)

Power Consumption

20 VA (heater)

Operating Environment

Operating Temperature: -50…60°C (with heater), Operating Rel. Humidity: 0…100% RH

Cable length

10 m

Protection Level



Compliant to IEC 61724-1:2017 Class C

Mast diameter

Mast diameter 60 – 76 mm

Solar Radiation

Response time (95%) : < 18 s
Non-stability (change/year) : < 1 %
Non-linearity (0 to 1,000W/m²) : < 1 %
Directional error (at 80° with 1,000W/m²) : < 20 W/m²
Temperature dependence of sensitivity : < 5 % (10… +40 °C)
Tilt error (at 1000W/m²) : < 1 %
Spectral range : 300…2800 nm
Measuring range : 2000 W/m²

Air Temperature

Principle : NTC
Measuring range : -50 … 60 °C
Unit : °C
Accuracy : ±0.2 °C (-20…50 °C), otherwise ±0.5 °C (>-30 °C)

Relative Humidity

Principle : Capacitive
Measuring range : 0 … 100 % RH
Unit : % RH
Accuracy : ±2 % RH

Air Pressure

Principle : MEMS capacitive
Measuring range : 300 … 1200 hPa
Unit : hPa
Accuracy : ±0.5 hPa (0 … 40 °C)

Wind Direction

Principle : Ultrasonic
Measuring range : 0 … 359.9 °
Unit : °
Accuracy : < 3° RMSE > 1.0 m/s
Resolution : 0.1

Wind Speed

Principle : Ultrasonic
Measuring range : 0 … 75 m/s
Unit : m/s
Accuracy : ±0.3 m/s or ±3 % (0 … 35 m/s) ±5 % (>35 m/s) RMS
Resolution : 0.1 m/s


Measurement range : 0 … 359°
Resolution : 1.0°
Accuracy : +/-10°
Sampling rate : 5 minutes

  • What is weather monitoring station?

    Weather monitor station:  Weather monitoring station is a facility with instruments and equipment for measuring atmospheric conditions to provide information for weather forecasts and to study the weather and climate. It is available with Solar Panel and Mounting Accessories.

  • What is weather monitor system?

    Weather monitor system: Collecting weather data like Wind Speed, Wind Direction, Precipitation, Air temperature, Relative humidity, Brightness, Twilight, Solar radiation, Barometric pressure, with the help of  data logger.

    A weather monitoring system consists following component.

    • Weather sensors (Wind Speed, Wind Direction, Precipitation, Air temperature, Relative humidity, Brightness, Twilight, Solar radiation, Barometric pressure)
    • Solar Panel
    • Data logger
    • Telemetry system
    • Data monitoring software.
  • What is weather monitor?

    Weather monitors: The periodic or continuous surveillance or analysis of the state of the atmosphere and climate, including variables such as temperature, moisture, wind velocity and barometric pressure is called weather monitoring.

  • What is weather detector?

    Weather detector: Weather detectors are also called weather sensor as per their name they detect changes in weather parameters.

  • What is weather sensor?

    Weather sensor: Weather sensors are sensor used to detect meteorological parameters data such as- Wind Speed, Wind Direction, Precipitation, Air temperature, Relative humidity, Brightness, Twilight, Solar radiation, Barometric pressure.

  • What is cast of Automatic weather station.

    Automatic weather station cost: AWS cost varies according to number of parameters and features, you can contact us to get best quote.

  • What are Automatic weather station components?

    Automatic weather station components: Typical AWS have the following components:

    • Anemometer for measuring Wind Speed.
    • Wind Vane for measuring Wind direction.
    • Pyranometer for measuring solar radiation.
    • Barometer for measuring atmospheric pressure.
    • Hygrometer for measuring humidity.
    • Rain gauge for measuring liquid precipitation.
    • Evaporation Sensor for measuring evaporation.
  • What is Automatic weather station?

    Automatic weather station (AWS) is automated version of conventional weather sensor. Which helps in monitoring all type of weather parameter like Wind Speed, Wind Direction, Precipitation, Air temperature, Relative humidity, Brightness, Twilight, Solar radiation, Barometric pressure.