toggle menu



ANACON: How does the connection and installation of the Analog Transmitter ANACON work?

In this short video we show you how to connect and install the Lufft Analog Transmitter ANACON:

To the Training Video of the ANACON

Show FAQ

CHM 15k: How to find/choose correct firmware version corresponding to your hardware version

A new firmware version for the CHM 15k comes in two hardware-dependent variants: 

  • Firmware version 0.xxx_550 (e.g. 0.743_550)
  • Firmware Version 0.xxx_552 (e.g. 0.743_552)

The version 0.735_552 and all subsequent versions X.XXX_552 apply to newer CHM 15k devices which have been built since June, 2015. From the installed firmware version 0.733 on, you can find the right update version through on the CHM web interface.

For devices with firmware versions before 0.733, you can recognize the compatibility by means of the OS version (web interface --> device tab "firmware"):

For OS: 12.12.1 please use the firmware version 0.735_550 and for OS: 15.06.1 the firmware version 0.735_552.

If you have uploaded the wrong version accidentially, the status bit 12 is set. You can install the appropriate version again.

You can find the new firmware in the download area of the CHM 15k product page.

Show FAQ

CHM 15k: In which applications is the ceilometer CHM15k in use?

The View into the Sky - Applications with the Cloud Height Sensor CHM15k! Watch our webinar recording where we present completely different application scenarios, where our cloud height sensor CHM15k can be the sensor of your choice!

To the webinar recording: Applications with CHM15k

Show FAQ

CHM 15k: On-site calibration & on-site check of the calibration - How to do? How often to do?

Lufft is offering a cloud simulator tool to check the instrument quality in field.

The simulator generates different light pulses and background light levels to test the detection unit and the data acquistion path of our CHM units. The starting point is the laser itself. The laser pulse is detected by the simualtor and time shifted LED pulses are generated. By comparision with the instrument specific production protocol the user can easily see differences in the calibration. The simulator takes a test time of 30 minutes in maximum and should be repeated once per year to verify the status of the system.

In case the instrument is showing an error or the results of the simulator are out of specs, the LOM (laser optic module) of the CHM instrument shall be exchanged. It can be repaired and recalibrated in lab.

Furthermore, on-site calibration in field can be done to achieve absolute backscatter values from aerosol layers. The absolute calibration can be done in two different ways:

1) comparision with another lidar instrument, which should have a sensitivity 10 times better than the ceilometer and should have at least the same range resolution of 5m.

2) clear sky calibration and specific rain cloud calibration ( both methods will be implented by the European Met services shortly. There is an ongoing project to deliver the algorithms. Please check: 

Advantage: The Rayleigh calibration and the cloud calibration method do not need additional equipment.

The on-site calibration takes 24 h to 1 week to be able to compare different cloud and aerosol layer situations. In a rainy season, in permanent low cloud, brown cloud or in foggy places the on-site atmospheric calibration might not work at all and our cloud simulator check of the lab calibration gives you the best result.

Show FAQ

CHM 15k: What is the minimum distance between two devices in order to prevent mutual interference of the backscatter signals?

A distance of 50 cm between the instruments is sufficient, provided that the levelling screws in the base of the instrument ensure a mutual tilting of 0.5°.

Show FAQ

CHM 8k / CHM 15k: Can the device be operated, restarted or deactivated remotely?

The device can be configured, restarted and shut down conveniently and password protected via the RS485 interface as well as via LAN/WAN and web interface.
Both the firmware and the operating system are restarted via 'restart system'.
Via 'shutdown system' the system is shut down and must be switched on again for a restart on site. Please take this into account, especially if the device is not installed in the immediate vicinity.
Please find a detailed description of the functionality in the manual.

Show FAQ

CHM 8k / CHM 15k: Can the status of the NTP query (time server) be verified?

As of firmware version 1.020, the web interface / page "Process Status" displays the server name, status of availability, current time offset, query interval, etc.

Note: If the time offset exceeds 1000 s (approx. 17 minutes), the iterative adjustment via the NTP protocol no longer works. The time must then be set manually, e.g. via the web interface, or the device must be restarted. The time is newly set at system startup when the NTP server is available.

Show FAQ

CHM 8k / CHM 15k: Does the device have a window contamination control?

Depending on the degree of soiling of the windows, a corresponding NetCDF variable (state_optics) is reduced from its original value of 100. A warning is issued when a certain limit value (70) is reached and the status code of the device is changed. This can be used as a recommendation for cleaning the windows.

Show FAQ

CHM 8k / CHM 15k: How should the device be installed in relation to the sun?

How should the device be installed in relation to the sun?

The device side with the door should face south. In case of high solar radiation (south of 35° northern latitude), the device should additionally be tilted to the north via an adapter angle in order to keep the influence of solar radiation as low as possible.

This applies to the northern hemisphere. For the southern hemisphere, the opposite cardinal directions apply.

Please consider that measurements against the sun are not possible for an optical measuring device.
We offer corresponding angle adapters as accessories. Please feel free to contact us on this subject.

Show FAQ

CHM 8k / CHM 15k: How should the NetCDF variables "time" and "range" be interpreted?

"time" means the end time of the measurement

"range" means the beginning of the range

Show FAQ

CHM 8k / CHM 15k: In which cases does the case fan start?

When the device is started: for typ. 2 minutes, in case of dirty or wet panes as well as detected rain, for cooling at interior temperatures > 39 °C and per default every hour for removal of dust, pollen, etc. To minimize possible noise pollution, the activation of the fan can be limited via the BlowerMode parameter. Please pay attention to the correctly set parameter TimeZoneOffsetHours for compliance with possible night/rest times. Further information can be found in the manual, chapter 8.1

Show FAQ

CHM 8k / CHM 15k: Is it possible to get the device-specific overlap data for own calculations?

The overlap data corresponding to your device can be sent to you in the form of a file. Please contact us at

Show FAQ

CHM 8k / CHM 15k: What are the maximum cable lengths for the CHM 8k / CHM 15k?

The standard cable length for power supply and data transfer is 10 m. Longer cable connections are also possible. Please feel free to contact us for this.

Show FAQ

CHM 8k / CHM 15k: What should be considered with regard to the use of SD cards?

Cards with a memory capacity of up to 32GB can be used from Speed Class 10 on. We recommend industry standard. Formatting must be done with FAT32 file system. Formatting via the web interface is possible and recommended. To change the card, the device must be shut down and externally disconnected from the power supply and secured against being switched on again.

Show FAQ

CHM 8k / CHM 15k: Why is Cloud Cover -2 displayed after starting the device?

For the calculation of the cloud cover at least the last 30 minutes of the measured data are used. Without the complete data (temporal) no calculation is possible -> "-2" is output.

Show FAQ

CHM 8k / CHM 15k: Why is there a delay in displaying data in the web interface or why is it only displayed after clicking "Update"?

Automatic display has been disabled on the Viewer page to keep traffic low on low data rate connections. The other data is updated every 15s. On the Process Status page, the data is updated every 60s.

Show FAQ

CHM 8k: What is the minimum distance between two devices in order to prevent mutual interference of the backscatter signals?

A distance of 10 m between the devices is unproblematic. A distance of down to 3 m is possible by slightly tilting both units by 0.5 ° each via the leveling screws in the opposite direction. For even smaller distances, adjustments can be made by OTT HydroMet. Please feel free to contact us for this purpose at

Show FAQ

DACON8: How does the connection and installation of the Digital-Analog-Transmitter DACON8 work?

In this short video we show you how to connect and install the Digital-Analog-Transmitter DACON8:

To the Training Video of the Digital-Analog-Transmitter DACON8

Show FAQ

IRS31Pro/ARS31Pro: How to install a Lufft Road Sensor?

MARWIS CloudGate: How do I setup the MARWIS CloudGate box?

In a short tutorial our technician Manuel Kreissig shows you which first steps you have to take to setup the CloudGate box (SIM card insert and wiring).

Watch CloudGate tutorial

Show FAQ

MARWIS: How large is the measuring spot?

The measuring spot of the mobile sensor is approx. 10cm x 10cm in the specified distance. This applies to both the 1m and the 2m version.
If the distance deviates from this, the measuring spot becomes correspondingly larger (with larger distance) or smaller (with smaller distance).
However, it should also be noted that the area of the transmitter and the receiver move further and further apart, as the MARWIS "squints" a little.

Show FAQ

MARWIS: What are the first steps to use MARWIS?

In this short movie our service expert Manuel Kreissig shows you the first steps to install and run the mobile road sensor MARWIS with your car.

To the MARWIS Tutorial: From installation to start-up

Show FAQ

OPUS20 and SmartGraph3: How to work with SmartGraph3 Monitoring Software?

In the tutorial video we answer many questions from first steps with OPUS20 and SmartGraph3 to different configuration options:

Startup OPUS20
- Installation SmartGraph 3 (03:18 min)

SmartGraph 3
- Software settings (05:05 min)
- Manage devices (07:21 min)
- Diagram view settings (10:22 min)
- data export (14:25 min)
- print function (15:15 min)
- Software- and firmware-update (16:58 min)

To the Tutorial Video:

Lufft OPUS20 Datalogger and SmartGraph3 Monitoring Software

Show FAQ

OPUS20 and SmartGraph3: Is SmartGraph3 (min. V3.2.0) compatible to Windows7/10?

OPUS20: How can the data be recorded in the internal memory of the OPUS20?

The OPUS20 must be configured in Mode M3 REC or M4 REC Hide. This can be done using the configuration button on the back of the OPUS20.

Show FAQ

OPUS20: Is ethernet communication available for all OPUS20 versions?

Yes, the etherent interface is a part of all OPUS20 instruments, so all of them cam be connected to the network (LAN)

Show FAQ

OPUS20: What are the eletrical specifications for the PoE version of the OPUS20 device?

OPUS20E: How to configure the OPUS20E datalogger?

In this video tutorial we lead you trough all the important points from installation to configuration:

  • Description of OPUS20E data logger
  • Configuration of external sensors without PC
  • Configuration via SmartGraph3 software
  • Answers to general questions

To the tutorial video:

Configuration of the Lufft OPUS20E datalogger

Show FAQ

SHM 30: How can I avoid that the sensor will be covered with snow (affected by very strong winds)?

A special tube may be added.


  • Front: 70mm
  • Middle: 100 mm
  • End: 50mm (connection to the sensor)

An extra Lufft accessory is planned for the future

Show FAQ

SHM 30: How to defrost a frozen sensor

You can fix a heater mat on the metal tube, e.g. with 10W power. This would also be the best way to defrost the window of the sensor. Hot water on a frozen window can lead to a serious damage and shall be avoided.

Show FAQ

SHM 30: What is the life time of the sensor?

Laser Diode Module (LDM) is the most critical part Expected life time:

  • >45,000 h (limited to laser diode MTBF; 4-5 years; runs normal between 100 000 to 200 000 hours)
  • MTBF: 45,000 h

Show FAQ

SHM31: How long would the sensor need to be on in order to be stabilized and to record proper data? Can the sensor be switched off for long periods of time?

Yes it can be switched off for a longer time. There is a defrost mode that can be activated by default, if the sensor is switched on in very cold environments. It can take 2 minutes or 10-15 minutes to wake up the sensor, depending whether the outer conditions are very cold (-40°C ) or moderate (-10°C).

Show FAQ

SHM31: If operating under SDI-12 communication protocol: Can the heater be turned on and off remotely using the SDI-12 command?

The heaters can be activated/deactivated also with SDI-12. Additionally the heaters could be deactivated with a voltage level at the red 3-pin (configurable).

Show FAQ

SHM31: Is it possible to measure water or ice with SHM31?

The SHM31 is mainly designed to measure the snow depth. The measuring principle is not applicable to measure pure ice or water due to strong reflections or translucency. For ice and water on roads please view also our road sensors like NIRS31, MARWIS/StaRWIS and ARS/IRS31Pro.

To the Lufft road weather sensors

Show FAQ

SHM31: What are the specific limitations of using the sensor on 12V?

There are no limitations. But current will be bit higher to get the same heating power as with 24V.

Show FAQ

SHM31: What is the minimum operating temperature of the sensor with the heaters turned off? At what temperature would it be necessary to turn the heaters on? How would turning the heater off affect the overall measurements of the sensor?

The sensor can operate without heater until -10°C outer temperature without heater. Turning the heater off above -10°C would first of all not affect the measurement, but the outer window might get opaque due to condensation/ freezing after a while.

Show FAQ

SHM31: What type of current draw does the heater have at 12 V (with and without the heater)?

The power consumption at 12 VDC is roughly: 2.5 W if only the window heater is enabled and 18 W with window and main heater switched on.

Show FAQ

SmartView3: How to install and configure the SmartView3 Software?

ViewMondo: How to work with ViewMondo Road Weather Management Software

In this short software training we show you all important functions of the ViewMondo road weather management software. It is suitable for both fixed and mobile road weather stations. Watch this video and see how user-friendly it is.

To the ViewMondo 5min Tutorial

Show FAQ

WS product family: Communication after protocol change

How to communicate with a WS-Sensor and the UMB-config-Tool if the protocol was changed for example to Modbus or SDI-12?

After a Reset ( switching On/Off the sensor) every WS-Senor will start up for the first 5 seconds in UMB-protocol and the standard baud rate of 19200Bd. Independend to the configured protocol and baudrate settings of the WS-Sensor.

In this first 5 Seconds you will be able to connect via UMB-config-Tool to the WS-Sensor after this first command was send the UMB-protocol will stay for 10 minutes after that it switches back to the original configured protocol. This Time will always be extended to 10 minutes if a new UMB command was send.

Show FAQ

WS product family: SDI-12 wiring plan for Device version >= 42

How to connect a WS-sensor with a device version >= 42 (hardware version >=14) to a SDI-12 system?

The wiring plan has changed compared to the wiring plan of older WS-Sensor device versions.
The new wiring plan is:

  • +VDD = brown
  • GND = white
  • SDI12_Signal = yellow
  • SDI12_GND = white

This is also mentioned as a note in the latest WS-sensor manual in the section 8 Connections

Show FAQ

WS100: How does the Doppler Radar Measurement Principle of the WS100 work?

The 24 GHz Microwave Doppler Radar works with the radar reflection method and measures the precipitation quantity or precipitation intensity by means of the correlation of drop size and velocity below the sensor.

Inside the the smart sensor a drop Size distribution matrix enables to calculate intensity of precipitation and to determine type of precipitation according fundamental meteorological relationships (Gunn-Kinzer and Hobbs and Locatelli).

More to read about the measurement principle in the WS100 Sensor Guide:

To the Download of the WS100 Sensor Guide

Show FAQ

WS800: What is the max. radius a lighting can be detected from the WS800?

The WS800 uses a integrated electronic chip to detect the lighting. The max. radius of this detection is approximately 10 Km.

Show FAQ

XA1000: Is it possible to calibrate temperature and humidity if I use the handheld device XA1000?

Yes, with the firmware version V1.9 or higher a calibration of the temperature and humidity is possible. You will be able to do a one point calibration (offset) directly in the handheld device XA1000.

Show FAQ