• functions: wind meter
  • measurement: wind speed and direction
  • small size
  • low price
  • two cable connection
  • digital measurement result transmission
Wiatromierz LB-747



Meter LB-747 is designed for measurement of wind speed and direction horizontal component. The meter is made basing on the mechanical WSD1 elements - that are produced in England. It is characterized by small size and low weight. It can be made in a version for wind speed measurement only (without a direction measurement - LB-747P). The meter is especially designed for work in small, portable meteorological stations.


The wind meter is made out of two sensors: a speed sensor and a wind direction sensor as well as a measurement converter. The meter's casing is made out of anodized aluminum alloys. The speed sensor has a small inertia vane made out with ABS (what assures quick response) placed on a double bearing made from stainless steel. Each vane rotation generates one impulse on the reed relay output. The direction sensor is dynamically balanced and is coupled with a potentiometer. The signals form the sensors are delivered to a measurement converter, placed in an additional casing on a mast or immediately in a meteorological station's casing (i.e. LB-741).

The electronic meter system is secured by a silicone filing compound which makes it resistant to high humidity and additionally has a metal screen which protects is (to some extent) against atmospheric discharge.

Work rule

The vane rotations are transferred to the magnet movements causing for the reed relay to short circuit. The impulse frequency coming from the reed relay is measured using the microprocessor's meters. The wind's direction is transferred to the position of the potentiometer's sliding head, which voltage is measured by the analog - digital converter integrated with the microprocessor. The electrical signals coming from the sensors are counted by the microprocessor - the calibration values stored in the device's memory are also taken into consideration. Additionally the wind's direction measurement results are averaged by taking the last eight measurements - in such a way the moment sensor oscillations around the perpendicular axis are eliminated.

The measurement results are sent from the device in a digital form (current loop) to a supervisory system of data collection:

The interface parameters allow on sending data and powering the device using one two cable screened line of any polarity, what makes the installation process a lot easier. The length of the transmission line is limited only by the resistance of the cable used (resistance of both cable wires cannot exceed 100 om).

LB-747 na maszcie

Meter assembly

The meter is assembled using an extension arm, offered as an additional meter's equipment. An extension arm is fastened to a horizontal mast from 30 to 50 mm in diameter. An example way of assembling on the meteorological station's mast using the extension arm is introduced on the picture below.

In order to secure the wind meter against the atmospheric discharge one should add to the set a lighting protector installation which should be placed next to the meter according to the general ways of using it. It is recommended to complement the cable connection with the cooperating device for a protector, i.e. a subscriber telephone protector type OA-1.


1 impulse for 1,493 m
Maximum wind speed
90 m/s
Minimal wind speed
0,5 m/s
2 %
2 %
Rotation range
360 ° (with no end)
Scope of work measurement
357 °
Accuracy 3 %
Linearity 0,5 %
280 mm
Diameter (maximum)
240 mm
Weight (without a converter)
500 g
Measurement resolution
speed: 0.1 m/s
direction: 1 °
Power supply
voltage 8...24V DC,
current 15...25 mA.
Interfejs digital current loop
Scope of work temperatures
-20...+70 °C
Elektronika Laboratoryjna Produced by: LAB-EL Laboratory Electronics
68b, Bodycha Str., 02-495 Warsaw
tel: (022) 667 71 18, 0601 209656, fax: (022) 867 53 32
e mail:
home page:
internet meteorological station:
meteorological station on a mobile phone:
Last updated: 09.05.2004
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