Measurement Modes of Digital Anemometers
Digital anemometers support two types of measurement: average wind speed and turbulence components (wind turbulence ranging from 1 to 150 kHz, different from ordinary airflow fluctuation).Common methods for average wind speed measurement include thermal, ultrasonic, impeller and pitot tube types.
The thermal method measures wind speed by detecting the resistance variation of an energized sensor cooled by airflow, yet it cannot provide wind direction data. Featuring portability and high cost‑effectiveness, this type is widely adopted as a standard anemometer product.Sensing elements of thermal anemometers may adopt platinum wire, thermocouples or semiconductors. Our company uses platinum coiled wire, which delivers excellent chemical stability. It ensures outstanding long‑term stability and superior performance in temperature compensation.
The wind direction sensor of the photoelectric anemometer adopts a low‑inertia lightweight metal wind vane to respond to wind direction and drive the coaxial code disc to rotate. The code disc is encoded with Gray code and scanned by optoelectronic elements to output electrical signals corresponding to wind direction.
The photoelectric wind speed sensor is equipped with low‑inertia wind cups that rotate with airflow and drive the coaxial light shielding disc. Optoelectronic scanning outputs pulse trains, and the pulse frequency corresponds to the rotational speed for convenient data collection and processing. It features high structural strength, sensitive start‑up performance and compliance with national meteorological measurement standards.
With a built‑in electronic compass, the wind direction sensor can automatically calibrate the azimuth angle. It is applicable to both fixed installation sites and mobile scenarios, such as special vehicles, ships and drilling platforms.
Rotary Probe of Anemometer
The working principle of the rotary probe for digital anemometers is to convert mechanical rotation into electrical signals. A proximity sensor counts the rotation of the impeller and generates a pulse sequence, which is processed and converted by the detector to obtain the rotational speed.Large‑diameter probes (60 mm, 100 mm) are suitable for measuring turbulent flow at medium and low velocities, such as airflow at duct outlets. Small‑diameter probes are more suitable for airflow measurement where the cross‑sectional area of the duct is more than 100 times that of the probe.
