Wind

Ultrasonic Anemometer 1D

The Ultrasonic Anemometer 1D serves for the acquisition of the horizontal air flow and direction in tunnels, tubes or similar applications. Due to the high measuring rate the instrument can be used also for the inertia-free measurement of gust- and peak-values.

• The measuring values are available via serial interface as analogue signals and/or data telegram.
• Analogue output:
  Flow speed with or without direction detecting.
• Digital output:
  Flow speed with direction detecting, and virtual-temperature.
• If necessary, the sensor branches are automatically heated with critical ambient temperatures. Thus, the function is guaranteed also with negative temperatures.

1. Mode of Operation
The Ultrasonic Anemometer 1D consists of 2 ultrasonic transducers which are opposite each other at a distance of 200 mm. The transformers act both as acoustic transmitters and acoustic receivers. When a measurement starts, a sequence of 2 individual measurements in 2 directions of the measurement paths is carried out at maximum possible speed. The measuring directions (acoustic propagation directions) rotate clockwise. Mean values are formed from 2 individual measurements, and are used for further calculation. A measurement sequence takes approx. 10 m/sec at +20°C.

2. Measuring Principle
The speed of an air flow superposes the propagation speed of the sound in silent air. An air flow in the propagation direction of the sound supports its propagation speed ,and leads to its raise. An air flow against the propagation direction, however, leads to a reduction of the propagation speed of the sound. The propagation speed resulting from the superposition leads to different running times of the sound at different air flows, and directions over a fixed distance of measurement. As the sound speed is much depending on the air temperature, the running time of the sound is measured in both directions, thus avoiding any effect of the temperature on the measuring result.
Order Code: 4.3860.00.340

Technical Data:

Characteristic	Description
Flow speed	Meas. range	0...20 m/s
	Accuracy	± 0.1 m/s , at the range 0 ... 5 m/s resp. ± 2 % rms from meas. value , at > 5 m/s
	Resolution	0,1 m/s
Recognition of direct.	Meas. range	1° / 181° (Info: 0° = calm)
Virtual Temperature	Meas. range	- 40 .... + 70°C
	Accuracy	± 0,5 K
	Resolution	0,1 K
Data output- digital	Output	Flow speed, - direction, and virtual-temperature As: Instantaneous value, gliding mean value 1sec; 10sec; 1min; 2min; 10min
	Interface	RS 485 / RS 422
	Baudrate	1200, 2400, 4800, 9600, 19200 selectable
	Output rate	1 per 100 m/sec up to 1 per 25.5 sec, selectable
	Status identification	Heater status, Path disturbance
Data output- analog	Output	Flow speed with and without recognition of direction(no virtual-temperature analog output) As: Instantaneous value, gliding mean value 1sec; 10sec; 1min; 2min; 10min
	Output signal	0 ... 20 mA (factory adjustment) or 4... 20 mA
	Electr. output 1	Direction-independent e.g. 0... 20 mA = 0... 20 m/s
	Electr. output 2	Direction-independent e.g. 0...10...20 mA = -20...0...+20 m/s
		Load at current output max. 400 Ohm
		Load at voltage output min. 4000 Ohm
	Update rate	1 per 100 msec
	Resolution	12 Bit
General	Internal meas. rate	400 measurements per second, at 25°C
	Temp. range	- 40 ... + 70°C
	Supply voltage	electronics, 12... 24 V AC/DC ±10%; ca. 3 VA
		heater, 24 V AC/DC ±15%: max. 35 VA
	Protection	IP 66
	Icing	acc. to THIES STD 012001
	Corrosion	No corrosion after 3 month of salt fog and condensation
	EMV	EN 55022 5/95 class B; EN 50082-2 2/96
	Model	V4A Stainless steel for housing and sensor arms
	Mounting	Flange plate with boring
	connection	3m cable via PG-screwing
	Weight	2,5 kg
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