Key features


  • 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
  • Maintenance-free operation – no moving parts that can wear out
  • Compatible with many commercially available Met/HydroMet data loggers and PLS systems thanks to an open communication protocol
  • Suitable for all climate zones; also for solar-powered automatic meteorological stations
  • Ventilated temperature and humidity measurement according to WMO guidelines


Relative humidity is measured by means of a capacitive sensor element; a precision NTC measuring element is used to measure air temperature. The world renowned technology of Kipp & Zonen CMP3 is integrated. Measurement output can be accessed by the following protocols: UMB-Binary, UMB-ASCII, SDI-12, MODBUS. One external temperature or rain sensor is connectable.

Lufft WS301-UMB

  • Temperature

    Principle NTC
    Measuring Range -50...60°C
    Accuracy ±0,2°C (-20°C...+50°C), otherwise ±0.5°C (>-30°C)

    Relative Humidity

    Principle Capacitive
    Measuring Range 0...100% RH
    Accuracy ±2% RH


    Response time (95%) < 18s
    Non-stability (change/year) < 1%
    Non-linearity (0 to 1,000 W/m²) < 1%
    Directional error (at 80° with 1,000W/m² < 20W/m²
    Temperature dependent of sensitivity < 5% (–10 bis +40°C)
    Tilt error (at 1000W/m²) < 1%
    Spectral range (50% points) 300 to 2,800nm
    Measuring range 1400W/ m²

    Air pressure

    Principle MEMS Capacitive
    Measuring range 300…1200hPa
    Accuracy ±0.5 hPa (0 … +40°C)

    General Information

    Protection type housing IP66
    Interface RS485, 2-wire, half-duplex
    Operating Power Consumption 12-24 VDC ±10%
    Operating Humidity Range 0...100%
    Operating Temperature Range -50...60%°C