Operating Manual V 3.3 / 9 Dec 2019
MARWIS-UMB
8 Mounting
8.1 Hints for mounting MARWIS-UMB
The mounting of the MARWIS-UMB on the vehicle must be fit to be used on the road.
The protective housings 8900.G01 and 8900.G02 are supposed to protect the sensor from tur-
bulences and dirt which could impair the measurement. They do not affect the measuring dis-
tance which has to be measured in any case between the sensor face and the road.
It has to be made sure that the field of view of the MARWIS-UMB is directed to the road and not
interrupted by vehicle parts. The zone that would be covered if the side parts of the protective
housing were extended down to the road should be free of obstacles. The inclination angle of
the MARWIS-UMB towards the road must correspond to the one which is given by the protective
housing (see illustrations in chapter 15.3).
The MARWIS-UMB should be installed in a way that ensures it cannot be affected by heat from
the exhaust fumes of the vehicle.
It should be avoided installing the MARWIS-UMB straight above the tyres track since in this
position the risk of spume soiling the glass front of the MARWIS-UMB is elevated which could in
turn affect the measurement of the water film height.
8.2 Hints for mounting STARWIS-UMB
STARWIS-UMB is supposed to be fixed stationary to a mast, sign gantry or similar. Lufft offers
the short protective housing together with a clamp for fixing it to pipes of 60 – 80 mm (2 ⅜ – 3 ¼
in) in diameter. Make sure that the view field of the STARWIS-UMB is directed towards the spot
which is supposed to be measured on the road and that the view line is not interrupted by any
obstacle.
8.3 Mounting height
The measuring distance of 1 m or 2 m (3¼ ft or 6½ ft) and 5.5 m (16 ⅜ ft) for the 2 MARWIS-
UMB types and the STARWIS-UMB respectively refer to the distance from the sensor front
(glass) to the road. This measuring distance should be observed as exactly as possible. The
tolerance which still allows for plausible measurement values amounts to -20 cm / +50 cm (-8
in / + 19¾ in) in case of instrument 8900.U03, -40 cm / +20 cm (-15¾ in / +8 in) for instrument
8900.U04 and ± 50 cm (19 ¾ in) for the stationary 8711.U55. If the STARWIS-UMB is mounted
on a mast, the distance of the mast to the measuring spot has to be taken into consideration. A
more detailed description will follow in the next chapters.
8.3.1 8900.U03, Mounting with short protective housing, angle 20º
Minimal height..........75 cm...(29 ½ in)..............measuring distance .......80 cm. .(31 ½ in)
Ideal height..............96 cm...(37 ¾ in)..............measuring distance .....100 cm. .(39 ⅜ in)
Maximum height.....141 cm...(55 ½ in)..............measuring distance .....150 cm......(59 in)
8.3.2 8900.U04, Mounting with short protective housing, angle 20º
Minimal height........150 cm.......(59 in)..............measuring distance......160 cm......(63 in)
Ideal height............188 cm.......(74 in)..............measuring distance .....200 cm. .(78 ¾ in)
Maximum height.....207 cm...(81 ½ in)..............measuring distance .....220 cm. .(86 ⅝ in)
Chapter 8, Mounting
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