FAQ - Frequently asked questions


At the moment only the binary UMB-protocol is available. More protocols will follow.

The configuration and the read out of data are possible over the UMB-Config-Tool. Through the ViewMondo software from MICKS measurement network data from both mobile and stationary sensors can be combined, visualized (e.g. by thermal mapping) and saved.More software solutions will be available from system integrators.

The sensor is technically compatible with all Bluetooth-enabled devices, which provide a virtual serial (COM-) port for communication. An Apple and an Android app are already designed and available. More software solutions will be developed through third-party suppliers in cooperation with Lufft.

That depends on the measurement frequency. For a normal data transmission only a low GPRS bandwidth is required. A higher speed is useful for downloading the map display.

The data volume depends on the number of sensor values and the update interval. Plus the dial-up and the map display (download function). If the sensor is on continuous operation with one transmission per minute, the data volume is estimated by 100 MB per month. With every second transmission of the data amount, the data volume will reach 3.0 GB per month. This are only appraised values. They can vary depending on the mobile device and measurement frequency.

For the calculation of the output measurement values, the internal collected measurands are watched for a certain adjustable time period and evaluated. For the weighting different presets can be chosen. On page 26 of the user manual a corresponding chart is shown. It is important, that the preset measuring rate match the query rate of the MARWIS, because the values change within this interval.

The frequency of the measuring value output is adjustable between an intervall of 100 milliseconds and 5 seconds. Which measurement point is displayed within this interval exactly, can be adjusted by using the road condition model. The related settings are located in the senor devices list, which you can enter via the Bluetooth connection icon on the dashboard display of the MARWIS app. Here you can choose between 6 presets: AVG (default setting), Winter 1, Winter 2, Winter 3, Summer 1 and Summer 2. What the different settings mean exactly, you can find out in the MARWIS manual on page 25f. It is important, that the preset measuring rate match the query rate of the MARWIS, because the values change within this interval.

MARWIS is equipped with an RS485, a Bluetooth interface and a CAN bus allowing a variety of possible communication connections.

You can check the connection status with the service channels 4040 and 4041. It reads out the signal strength.

Due to the mechanical vehicle structure (metallic partition walls, length of the vehicle, etc.), the distance between the sensor and the output device (tablet or smartphone) can be too large for a stable Bluetooth connection. Therefore, please keep the distance as short as possible in order to avoid interferences.


The data will be transmitted to the server by a binary protocol, so that there is no encryption between MARWIS and the iPad. The app on the iPhone/ iPad has no access to “critical” sections, only to GPRS, Bluetooth and the network.

The Data Providing contains of the cloud-based ViewMondo software package. For this, you get an own ViewMondo password-protected account for your mobile and fixed measurement stations. The data will be stored on the Lufft server. With ViewMondo portal you can query, archieve and process the data. providing portal. Since this is associated with an expense incurred for each MARWIS, this offer cannot be transferred to several MARWIS. An annual data providing payment accrues for each MARWIS device. More info on the related Lufft Blog post.

New updates will be provided regularly on the Lufft website and can be installed on MARWIS with the UMB-Config-Tool or the iPad.

The iOS/Android app includes road condition views on maps, shows all selected values like road temperature, friction, water film height, road condition etc., can adjust the sensor and transfers the data to a (ViewMondo) server.

A detailed descriptions of all features of the iPad app can be found at ios-help.lufft-marwis.com.

A few software options are already available by system partners like Applied Information, the telematic system from mm-lab. More solutions will follow.

MARWIS itself will not generate NTCIP output, but there are other possible conversion solutions (SmartView3, datalogger etc.).

Yes, it is possible to connect your mobile device (iPad, iPhone, or Android) with an external GPS receiver to improve the accuracy of the GPS localization. For the iPad / iPhone we tested a model, which is attached directly to the iPad / iPhone connector and works very well (details: “Bad Elf” GPS Receiver for iPad and iPhone, costs about 150 euros).

MARWIS is able to be connected to one mobile device only. After the first established Bluetooth connection, MARWIS tries to reconnect to the same Android device automatically. Therefore, the currently saved Android device needs to be changed. For this, first make sure that the Bluetooth interface of the previous MARWIS connection partner is disabled or out of reach. Also, check if a valid pairing between the new Bluetooth device and the MARWIS sensor consists (in the system settings of the Android device). To initiate the connection, open the MARWIS app. Then, open the list of available MARWIS through the device connection icon in the upper corner to the right. Please click on the MARWIS with which it needs to be paired. After a short time, the Bluetooth connection is established and the former connection partner in the MARWIS is overwritten.

MARWIS is able to be connected to one mobile device only. After the first established Bluetooth connection, MARWIS tries to reconnect to the same iOS device automatically. In order to change the iOS ouput device, please make sure that the former connection partner is out of reach or disabled. Afterwards, please check if the pairing between the new Bluetooth device and the MARWIS sensor consists. Then, go to settings –> Bluetooth –> other devices –> “MARWIS-UMB-XXXX.XXXX” and tap on the MARWIS to which the connection shall be esablished. Through this the Bluetooth connection will be esablished and the former MARWIS will be overwritten. Also in the MARWIS app the new sensor will be available.


The TFF sensor should be changed once a year. You can also reorder and install it by yourself. The optics needs to be calibrated once per vehicle. This can be made via the Android/ iOS App in a few simple steps. The application also allows to store different calibration profiles for different vehicles. Therefore you don’t have to calibrate the optics with every vehicle change. However we recommend a calibration interval of every 3 months.

MARWIS is equipped with a combined temperature-humidity-sensor. It is included in the delivery. The sensor should be changed once a year, to provide an exact as possible capture of temperature and humidity. This can be done by the user on site.

The data are not saved, but the configuration will survive.

When the Bluetooth connection between MARWIS and mobile output device is interrupted, no data will be saved. If the connection between the output device and the server is interrupted, the app saves the data and transfers them with the next connection to the server. The duration of the saving depends on the storage capacity of the main storage. Normally the main storage is about 2 GB, which is enough for several hours.

The GPS position will be determined by the smartphone or tablet.

MARWIS measures the following data:Dew point temperature, road surface temperature, relative humidity over the road surface, water film height and road condition (dry, wet, moist, frozen, snow/ice, critical wetness)

The relative humidity close to the street behaves differently from the one in the ambient air and represents a more exact picture of the actual road weather conditions (micro climate). For instance the question when white frost arises can be answered better with this value. With MARIW 2.0 the relative humidity in the ambient air can be determined as well.

The dew point temperature is the temperature, at which water steam in form of dew or fog separates from wet air. At the dew point the relative humidity counts 100 percent respectively it means that the air is (just) saturated. The dew point temperature for MARWIS is independent from the relative humidity directly above the road surface. This is why it delivers more important data for the road safety than the air temperature.

The cigarette lighter of a normal passenger car has a voltage of 12 Voltage. But in order to reach the maximum heating requirement of the MARWIS 24 Volts are required. If your MARWIS often runs with a yellow status LED continuously, we recommend a DC / DC converter such as the Samlex Step Up Converter Step 7 (price about 100 $ on Amazon).

The pyrometer measurement is never adjusted automatically, only manually. Therefore an offset for the pyrometer can be configured in the sensor settings. Precondition is an installed sensor firmware version from 1.8 on and an iOS app version from 1.5 on. Please measure the road temperature with a reliable reference instrument at the same spot, after MARWIS has been running for at least 10 minutes and the LED have switched to green already. Then, adjust the temperature measurement in the setting menu. For this, the –/-/+/++ buttons must be pushed until the wished temperature is reached (after pushing the buttons wait until the pyrometer is updated with the new emission level). Sensor configuration description on iOS app help as well as on the Android App help website.

Since firmware version 23 MARWIS can be used with CAN-BUS on default.

In principle, you have the free choice of the Android tablet. However, it is recommended that it has a 8-inch display size maximally in order to avoid an interference with the street view, such as the Samsung Galaxy Tab 4 (7.0, LTE). Also, it only works with the Android version 4.1 or newer. For the use with ViewMondo, MARWIS requires an UMTS/ LTE (international 3G / 4G) sim card.

Generally the display must never be switched off for the guaranteed data transfer and the app must be running in the foreground. In case the vehicle is at a standstill for a while, the data acquisition is turned off by default after 10 minutes. In the device settings, this time can be extended to 2 hours for stationary operation. In display mode, the standard charger is not sufficient for charging. We recommend to e.g. use the Belkin car charger (2.4 Amp/ 12 Watt). Then the battery of the iPad is also loaded when the display is always switched on.

The new MARWIS version is equipped with an additional temperature humidity sensor, which is visible in the sensor component’s description at “specifications”. This new element measures the ambient temperature and detects the ambient relative humidity.


At road salt vehicles and trucks, MARWIS can be installed sideways downwards (one-meter version). At cars, the sensor will be installed on the roof with the help of a magnet frame backwards (two-meters version).

The closer MARWIS is installed within a special area, the better are the measurement results. (one and two meters versions).

Tolerance limit for one-meter version: 0,75 – 1,25 m
Tolerance limit for two-meters version: 1,7 – 2,3 m

There are two versions: MARWIS for two meters distances and MARWIS for one-meter distances. The version with one-meter distance is more suitable for road salt vehicles and trucks. The two meters version is optimal for cars. The distance refers to the hypotenuse of the triangle (measuring axis), in which the sensor will be installed (distance between MARWIS glass plate and ground; the measuring axis lies up in the right angle on the glass plate).

Theoretically, yes. But probably on big vehicles like trucks MARWIS will be installed sideways and on cars backwards on the roof. It is recommended to use the different devices for the according vehicles, in this occasion.

No, because the Lufft rack solutions are only suitable for determined kinds of vehicles: usual passenger cars (horizontal rack) and vans with metal doors (vertical rack). All other kinds of cars, not meeting the given car sizes and conditions need a special and individual solution. We highly recommend complying with the specifications regarding the vehicle mounting (in the right angle and the right distances) as explained in the user manual . Lufft assumes no liability for faultily mounted racks.

As the magnets’ position can be changed flexibly, it is possible, that the mounting can be faulty. In order to ensure the right handling of the rack, you can find a list with examples under the following link: Here you get to the examples

The following two technical drawings explain how the final installation needs to look like:



MARWIS should be installed in a way that the measuring area is free (calculating with the triangle measure distance/ installation height). Besides that, a safety distance on the road with a radius of 0.3 meters around the measuring area should be provided to minimize optical spreading effects. As long as the measuring area is free, other traffic impacts at this part have no influence on the measurement.

No, because the installation is same as a cargo securing.

80 km/h is not the maximum speed. The faster the speed is the bigger is the distance between each measuring point. MARWIS is not tested by Lufft on a speed over 85 km/h. Users of the sensor should collect own experience on their operation scenario.

No, there aren’t any additional certificates needed, because MARWIS is mounted on the car directly and there are no changes of the airport infrastructure needed.

In the adaptation the basic settings are defined which are determined by the nature of the surface, the measured angle and the exact measuring distance between MARWIS-UMB and the road surface. First of all, the measuring distance between the sensor and the road has to be within the tolerance. The road surface should be representative for the area in which the MARWIS-UMB will be used. The ambient temperature should be lower than 20°C but not below 9°C. The adaptation must not be performed in artificial light.

MARWIS has passed the following TÜV tests successfully: EMC (Electromagnetic Compatibility), vibration, shock, IP69 and eye safety.

Please note the following:
– The accuracy of MARWIS is 0.8K (Kelvin) at 0 ° C
– The accuracy of the reference equipment shall be taken into account
– In case the MARWIS is mounted close to the vehicle’s exhaust pipe, the measurement can be interfered by gases
– Since the MARWIS measures contact-less, the reference device also needs to be contact-less, so that a comparison is possible

– Thermo-elements are no suitable reference instruments
– MARWIS’ measurement spot has a diameter of 20 cm for the one meter version and a 40 cm diameter for the 2m version. In this area, the temperature is averaged. If the reference device has another spot diameter on the ground, it delivers different results.
– Both MARWIS and the reference instrument must be in a thermal equilibrium, so that the temperature measurement is running properly. The MARWIS warmup takes about 10-15min.
– The road should be in a thermal equilibrium as well, thus, there shouldn’t prevail wind, direct sunlight, etc.