Preparation For Use; North Alignment - Thies CLIMA Ultrasonic Anemometer 2D Operating Instructions Manual

10. Preparation for Use

10.1 Selecting the Site
As already described above the ultrasonic anemometer transmits sonic bursts which are necessary for the
measurement of the propagation speed. If these sonic bursts hit a well sonic-reflecting surface they are
reflected as echo and might cause error measurements – under unfavourable conditions.
It is, therefore, advisable to install the US-anemometer with a minimum distance of 1 meter to objects in the
measurement area.
In general wind measurement instruments should be able to detect the wind conditions over a wide area. In
order to obtain comparative values when determining the surface wind, measurements should be taken at a
height of 10 meters above a plane, unobstructed area. An unobstructed area is one where the distance
between the wind transmitter and any obstacle is at least 10 times greater than the height of the obstacle. (s.
VDI (German Engineers Association) 3786). If this requirement cannot be fulfilled, then the wind
measurement instrument should be set up at a height where the measured values are not influenced by any
local obstacles (approx. 6-10 m above the level of the obstacle). The anemometer should be set up in the
center of flat roofs, not at the edge in order to avoid possible preferred directions.
10.2 Mounting the wind transmitter
The wind transmitter can be mounted to a pipe piece of R 1 ½" (Ø 48.3 mm) which is 50 mm long. The
internal diameter of the pipe must be at least 40 mm as the wind transmitter is connected electrically from
below with a plug. Solder a flexible control line LiYCY with the corresponding number of cores to the
enclosed plug. After the wind transmitter has been connected, set it onto the pipe piece respectively the mast
piece and align to North with the north sensor marking (red ring at the sensor). To do this, take a bearing via
the ultrasonic transducer of the North/South path onto an object to the North, for example a building or a
special geographic feature. Use the four screws with hexagonal recessed holes (SW 4 mm) to attach the
instrument to the shaft.
Note : When using a lightning rod please take care that it is mounted always in an angle of
45° to the measuring distance, as otherwise there might be deviations of measuring
value.

10.3 North Alignment

For the alignment of the anemometer the red marking of the sensor must indicate to the North. For this,
you select an obvious point in a northerly or southerly direction in the surroundings with the aid of a compass;
then turn the mast or the anemometer into this direction until both arms opposite are situated in a straight
line.
It is also possible that oneself stands in a northerly or southerly direction with respective distance, and a
partner turns the anemometer or mast by command until both sensor arms are situated in a straight line.
In this case, it is advisable to use a pair of field glasses.
11. Accessories
Connecting cable, complete
PC Software Online Wind
Power Supply Unit
RS 232 / RS 422 converter
Lightning Rod
506 702
9.1700.97.010
9.3388.00.000
9.1702.20.000
4.3100.99.000
11 -12
15 m cable with connecting plug
For visualization of data on PC screen
For the power supply of the Ultrasonic
For signal conversion of RS 422 in RS 232
For lightning protection
021235/10/01