The Ultrasonic Anemometer 3D consists of 6 ultrasonic transformers, in pairs facing each other at a distance of 200mm. The three resulting measurement paths are vertical in relation to each other. The transformers function both as acoustic transmitters and receivers. The electronic control system is used to select the respective measurement path and its measuring direction. When a measurement starts, a sequence of 6 individual measurements is performed in all 6 directions of the measurement paths in a preselect able timing cycle.
The measuring directions (sound propagation directions) rotate clockwise (looking from above), firstly from top to bottom and then from bottom to top. The mean values are worked out from the 6 individual measurements of the path directions depending on the measuring speed and output rate selected and used to make further calculations. The time required for a measuring sequence is approx. 3.5m sec at +20°C with the maximum measuring speed, which is only limited by the sound velocity over the measurement paths.
Output: Output of the measured values can be either digital and / or analog.
|An RS485/422 is available for serial communication. It can be operated in full or half duplex mode. For output of the measured values there are a number of predefined telegrams or a user-defined telegram (e.g. wind velocity, wind direction, acoustic virtual temperature, standard deviations, covariances, status information, etc.).||The X Y and Z-components of the wind velocity vector are output either as a current or voltage signal. Alternatively, the analog outputs can also be switched as analog voltage inputs (max. 5). Data is then output only via the serial interface with the user-defined telegram (with 3 inputs in half duplex mode; with 5 inputs, 2 in multiplex with serial COM).|
For a multitude of applications the contiuous output of solid measuring data of the wind velocity and direction is an indispensable requirement to the measuring system, even under meteorological extreme conditions such as icing situations. The Ultrasonic is, therefore, equipped with a sophisticated heating system. This system keeps all outer surfaces that might disturb the measuring value acquision in case ice formation, efficiently on a temperature above +5°C. Also the measuring arms belong to the heated outer surfaces, as well as additionally the ultrasonic transducer and the housing – depending on the model.
Please take into consideration here, that the weakest link of the chain determines the complete functionality. Instruments heating only a part of the construction rarely shows advantages compared with completely unheated instruments. The Utrasonic is in a position to generate measuring data with high accuracy even in unheated state at temperatures of up to below –40°C. There is no temperature-depending quality of the measuring data. The heating is necessary only for avoiding the ice formation on the instrument construction, thus avoiding an involved failure in the measuring value acquistion. The heating system avoids effectively an icing formation – depending on the model acc. to our inhouse icing standard THIES STD 012002.
- More than 70 different measurement values are available, such as:
- Wind velocity in X / Y / Z –direction.
- Total wind velocity.
- Wind velocity azimuth.
- Wind direction azimuth.
- Wind direction elevation.
- Acoustic-virtual temperature [°C].
- Standard deviation of wind velocity in X / Y / Z- direction.
- Standard deviation of the total wind velocity.
- Standard deviation of the wind velocity azimuth.
- Standard deviation of the wind direction azimuth.
- Standard deviation of the wind direction elevation.
- Standard deviation of the acoustic-virtual temperature.
- Statistic functions such as variance, covariance, turbulence intensity.
- Wind velocity X / Y / Z of the gust acc. to WMO.
- Wind direction of the gust (elevation) acc. to WMO.
The device is particularly suitable for use in
- Traffic engineering, aviation and navigation.
- Indoor flow measurement.
- As well as for alpine applications.