Lufft WS401 Compact Weather Sensor

Lufft WS401 Compact Weather Sensor

The WS401 accurately measures:
  • Air temperature
  • Relative humidity
  • Air pressure
  • Precipitation – Tipping Bucket
  • Serial Output – RS485 Modbus or SDI-12
  • Low power consumption
  • Aspirated radiation shield
  • Optional remote temperature probe


Lufft WS401 all-in-one compact weather station

The Lufft WS401 is ideal for measuring air temperature, relative humidity, solar irradiance, and air pressure. It is suitable for high-end applications where accuracy and build quality cannot be compromised.

The sensors are protected by a radiation shell for protection and to ensure measurement accuracy, making the WS401 compliant according to WMO guidelines.

The top-mounted tipping bucket rain gauge provides excellent measurements of precipitation. The gauge means you do not need to have a separately mounted rain gauge, so no requirements to make a separate plinth.

The WS401 is suitable for all climates, with a temperature range of -50 to +60 °C. There are no moving parts and data processing is built-in. This makes the WS400 incredibly robust and easy to use.

As standard, we supply the Lufft WS401 with Modbus communications. However, it is possible to supply the sensor with SDI-12. Please let us know at the time of ordering which you would prefer.

As with all WS series compact weather sensors, it is possible to fit a temperature probe. The probe measures surface temperature and is ideal for the PV solar sector to measure the back of panel temperature.

Dimensions Ø ca. 150mm, height ca. 380mm
Weight Approx. 1.5 kg
Interface RS485, 2-wire, half-duplex
Power supply 11 to 32 VDC
Power supply 5 to 11 VDC (electronics with limited precision of measurements)
Power supply 24 VDC +/- 10% (heater)
Power consumption 40 VA (heater)
Operating temperature -50 to 60°C (with heater)
Operating rel. humidity 0 to 100% RH
Cable length 10m
Protection level housing IP66
Mast mounting suitable for mast diameter 60 – 76mm
Principle  NTC
Measuring range  -50 to 60 °C
Unit °C
Accuracy ±0.2 °C (-20…50 °C), otherwise ±0.5 °C (>-30 °C)
Relative humidity
Principle Capacitive
Measuring range  0 to  100 % RH
Unit % RH
Accuracy  ±2 % RH
Air pressure
Principle MEMS capacitive
Measuring range  300 to 1200 hPa
Unit hPa
Accuracy ±0.5 hPa (0 to 40 °C)
Precipitation (Tipping bucket)
Resolution 0.2 mm
Accuracy ±2 %
Max. intensity 360 mm/h
Precipitation with reduction ring
Resolution 0.5 mm
Accuracy ±2 %
Max. intensity 144 mm/h

WS Series Frequently asked questions.

How do I mount my WS sensors? 

The sensor can be mounted directly onto a 60mm diameter pole. The sensors come with ‘U’ mounting brackets. A mounting arm (which can attach to 40-80mm diameter poles) can be supplied too.

Are other communications protocols possible?

Possible interfaces are RS485 with supported protocols UMB-Binary, UMB-ASCII, Modbus-RTU, Modbus-ASCII, XDR, and SDI-12.

What data logger is the WS401 compatible with?

The WS401 is compatible with many commercially available Met/HydroMet dataloggers and PLS systems thanks to an open communication protocol.

Optional Extras:
  • External temperature probe (can be used as a back of module temperature sensor)
  • Rain gauge Lufft WTB100