Meter LB-746 is designed for speed and direction measurement of wind
level component. The meter is made basing on the mechanical elements,
produced by the Young USA company. Originally, it was designed for
marine usage (sea buoys) that is why it is characterised by high
corrosion and small weight.
The meter's casing, a vane and the majority of internal components are made out of plastics resistant to UV radiation and corrosion caused by air salinity and other atmospheric pollutants. The vane's ball bearings and a vertical axis meter rotation are made out of stainless steel. Air tightens is assured by teflon seals and special grease that has low and constant friction factor in a wide scope of temperatures.
The meter's electronic system is protected against moisture by a silicone filling and additionally has a protective (to some degree) metal screen against atmospheric discharges.
Four blade propeller’s turns get carried to movement of six pole magnet creating variable current of frequency proportional to wind speed in a coil. The coil is placed in a motionless part of the meter. The signal’s frequency is measured using the microprocessor sensors.
Wind direction gets carried on to a potentiometer’s slide placement, which voltage is measured using an analog-to- digital converter integrated with the microprocessor.
The electric signals from the sensors are counted in the microprocessor taking into consideration the calibration factors saved in the program memory. Additionally, wind direction measurement results are averaged for the last eight measurements and because of it sensor's momentary oscillations around the vertical axis are eliminated. These results are sent from the device in a digital form to a supervisory system of the data collection.
The device is equipped with a digital current interface of time courses analogous with RS232C standard. The interface except for data transmission is used for powering an anemometer - using for this purpose two cable line (i.e. type used in telephone installations), where a polarity of attaching the interface cables is free.
The measurement results are sent from the device in a digital form
(current loop) to a supervisory system of data collection: a
LB-741, to a
LB-486, to a special reading
LB-724 or portable
LB-755 or (with using a
LB-371) through interface RS-232C to a PC computer. The interface
parameters allow on sending data and powering the device using one two
cable screened line of any polarization what simplifies the
installation. A transmission's line length is limited only by
resistance of the cable used (the resistance of both cable's wires
cannot exceed 100
The meter is assembled using a clamping ring on a vertical pipe 1" with an outside diameter of 34 mm. There is an additional ring in a set, which allows on memorizing a relation's direction during conservation.
In order to protect the wind meter from atmospheric discharges it is
recommended to complement the set with a lightning protector
installation in immediate neighborhood of the meter, according to
generally accepted work principles. It is also recommended to
complement cable connection with a cooperating device for a protector
i.e. subscriber telephone protector type OA-1.