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VS20k-UMB Visibility Sensor

Make: Lufft                                      Model: VS20k
✅ Suitable for extreme ambient conditions, active spider defense, seawater resistant, compatible interfaces.
✅ Measurand: Visibility (MOR) 45° forward scattering
✅ Sensor Type: 45° forward light scattering
✅ Signal Output: RS485 (2-wire, half-duplex); Analogue output (4 – 20mA)
✅ Supplied With:  10 m Standard Cable, Factory test/ Calibration Certificates.

VS20k-UMB Visibility Sensor:

The VS20k-UMB Visibility Sensor is a device designed for measuring visibility in a variety of environments. Visibility is a measure of how far and how clearly one can see, and it is an important parameter for meteorology, air quality monitoring, and transportation safety. The VS20k-UMB Visibility Sensor uses an advanced laser scattering technology to measure visibility, and it is suitable for both indoor and outdoor use.

The VS20k-UMB Visibility Sensor uses a laser beam to measure visibility by scattering light off of particles present in the air. The sensor then uses the scattered light to calculate the visibility in the area. The sensor has a wide measurement range, which makes it suitable for use in a variety of environments.

The sensor is highly accurate, with an accuracy of ±10% visibility and a resolution of 1 m, making it suitable for professional use. The sensor also has a fast response time, which allows it to quickly adjust to changes in visibility. It also has built-in temperature and humidity compensation, which helps to minimize errors due to changes in weather conditions.

One of the key features of the VS20k-UMB Visibility Sensor is its compact and lightweight design, which makes it easy to install and maintain. The sensor can be connected to a variety of data loggers, weather stations and other monitoring systems via standard digital output. The sensor also features a user-friendly interface and easy to understand data display, making it easy to operate.

The VS20k-UMB Visibility Sensor is suitable for a wide range of applications, such as air quality monitoring, weather forecasting, airport operations, transportation safety and many more. It is a reliable, accurate, and easy-to-use device that is suitable for professionals in various industries. With its advanced laser scattering technology, the VS20k-UMB Visibility Sensor provides accurate visibility measurement and helps to increase safety and efficiency in transportation, as well as provide meteorological data for weather forecasting and atmospheric research.

The VS20k-UMB Visibility Sensor measures visibility up to 20 000 m, making it ideal for highway, motorway, and bridge traffic applications. A calibration device is available (optional).
The VS20k-UMB is configured via the software UMB Config Tool:

  • Reading or changing the current configuration,
  • Calibration,
  • Polling of the current measurement values
  • The software allows configurations to be loaded and stored.

The measurement data is available for further processing in the form of the standard protocol Lufft UMB.

ASD = Active Spider Defense: The built-in vibrating motor ensures at irregular intervals that the VS2k visibility sensor is not so prone to spiders. The construction of VS2k also reduces the frequency of maintenance.

Application and features of VS20k-UMB Visibility Sensor:



✅ Road Weather Information Systems for road and traffic control systems
✅ Weather stations at marinas, onboard ships, and transportation
✅ Wind turbine control
✅ First and only visibility sensor with active spider defense
✅ Measurement range of 10 … 20’000m, ideal for traffic applications
✅ Sharp measurement resolution of 1m
✅ Easy and smart calibration thanks to a calibration kit (optional)
✅ Forward light scattering technique
✅ Long life time thanks to sea waterproof housing
✅ Open and free to use communication protocol for easy integration in existing systems







Approx. 4kg

Protection type



RS485 (2-wire, half duplex); Analogue output (4 – 20mA)

Value update


Included in delivery

Connection cable

Cable length


Storage conditions

Admissible storage temperature:-40…+70°C
Operating rel. humidity: 0…100% RH (non condensing), 0 … 98% (inside packaging)

Operating conditions

Operating temperature -40…+60°C
Operating rel. humidity 0…100% RH
Power supply 20…30VDC; typical 24VDC
Power consumption < 200mA (motor running and current outputs active), about 100mA in normal mode and RS485 output
Power consumption 3W (typical), 10W (max.)
Protection class III (SELV)


45° forward scattering

Measuring range

10 … 2000 m

Measuring resolution

1 m




±10% visibility

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