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WS400-UMB Smart Weather Sensor

Make:  Lufft    Model:  WS400 UMB
✅ Compact all-in-one weather sensor, low power, heater, aspirated radiation shield, maintenance-free operation, open communication
✅ Measurand: Temperature, relative humidity, precipitation intensity, precipitation type, precipitation quantity and air pressure
✅ Principle Used: NTC/T, Capacitive/RH, MEMS capacitive/Pressure, 24 GHz Doppler radar/Precipitation
✅ Signal Output: RS485 with supported protocols UMB-Binary, UMB-ASCII, Modbus-RTU, Modbus-ASCII, XDR and SDI-12
✅ Article number:8369.U01, 8369.U01-NA, 8369.U02

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, precipitation intensity, precipitation type, precipitation quantity and air pressure. One external temperature sensor is connectable.

Advantages of the Smart Weather Sensor WS400:

  • All-in-one housing concept of a compact weather sensor combining several measurement parameters in one housing with only one cable connection
  • 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

Application of the Smart Weather Sensor WS400:

The robust and maintenance-free smart weather sensor WS400 is designed for professional meteorological applications in all climate zones. It delivers reliable data, even in extreme ambient conditions.

  • 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 environmental data is needed…







Ø ca. 150mm, height ca. 380mm


Approx. 1.3 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 Temperature

-50…60°C (with heater)

Operating Rel. Humidity

0…100% RH

Cable Length


Protection Level Housing


Mast Mounting Suitable For

Mast diameter 60 – 76 mm

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)

Precipitation (liquid)

Droplet size: 0,3 … 5 mm
Detection sensitivity: 0,01 mm/h
Particle velocity: 0.9 … 15.5 m/s
Precipitation types :rain/ snow
Solid precipitation: 5.1 … ~30 mm
Intensity range: 0…200mm/h
Intensity resolution: 0.01 mm/h
Amount resolution: 0.1 mm
Accuracy: 20 % under laborary conditions
Reproducibility: Typical >90 % under laborary conditions