Thies CLIMA Ultrasonic Anemometer 2D User Manual

Ultrasonic Anemometer 2D
Operating Instructions 4.3800.00.940
1. Range of Application
The Ultrasonic Anemometer 2D is designed to detect the horizontal components of wind speed and wind
direction in two dimensions as well as the virtual temperature. Due to its very short measurement intervals,
the instrument is ideal for the inertia-free measurement of gusts and peak values.
In certain weather situations the accuracy of the air temperature measurement (virtual-temperature)
surpasses that one of the classic method where the temperature transmitter is used in a weather and thermal
radiation shield.
The measured data are available as analogue signals and as a data telegram via a serial interface.
The ultrasonic transducers as well as its carrying arms are automatically heated so that the measuring
results, in case of critical ambient temperatures, are not affected by icing rain or snow.
2. Mode of Operation
The Ultrasonic Anemometer 2D consists of 4 ultrasonic transducers, in pairs of 2 which are opposite each
other at a distance of 200 mm.
The two measurement paths thus formed are vertical to each other.
The transformers act both as acoustic transmitters and acoustic receivers.
The respective measurement paths and their measurement direction are selected via the electronic control.
When a measurement starts, a sequence of 4 individual measurements in all 4 directions of the
measurement paths is carried out at maximum possible speed.
The measurement directions (acoustic propagation directions) rotate clockwise, first from south to north, then
from west to east, from north to south and finally from east to west.
The mean values are formed from the 4 individual measurements of the path directions and used for further
calculations.
A measurement sequence takes approx. 10 msec at +20°C.
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Thies CLIMA Ultrasonic Anemometer 2D Specifications

General

Measurement Principle	Ultrasonic
Wind Direction Range	0 to 360°
Resolution Wind Speed	0.01 m/s
Resolution Wind Direction	0.1 °
Protection Class	IP 66
Accuracy Wind Direction	±2°
Operating Temperature Range	-40 to +70°C
Output	Analog
Power Supply	12 to 30 VDC
Wind Speed Range	0 to 60 m/s

Summary

1. Range of Application

2. Mode of Operation

3. Measurement Principle

3.1 Wind Speed and Direction Measurement

Explains how sound propagation time is used to determine wind speed and direction, compensating for temperature.

3.2 Acoustic-Virtual Temperature

Details how sound speed measures virtual temperature, independent of pressure but affected by humidity.

4. Technical Data

4. Measurement Parameters

Specifies measurement ranges and accuracies for wind speed, direction, and virtual temperature.

6. Interface Description

6.1 Telegram Forms Overview

Introduces the different digital telegram formats (VD, VDT, V4DT, NMEA) used for data transmission.

7. Averaging Procedure

8. Bus-Ability and Synchronization

9. Control Command List

9.1 Command Reference

Lists all available commands and their functions for controlling the Anemometer 2D via serial interface.

9.2 Command Input Procedures

10. Site Preparation and Mounting

10.2 Wind Transmitter Mounting

10.3 North Alignment Procedure

13. Calibration