E' tutto fisso qui... non varia proprio nulla.
Da uno dei manuali leggo: "The voltage should pulse from about 2.1 volts to close to 8 volts. If the wind is driving the anemometer too fast, the voltmeter may not be able to read the pulses. If the rotational speed of the anemometer is less than one rotation per second you should see the pulses. If you do not see pulses at a slow rotational speed, then the sensor has failed."
Basta, lo restituisco.