The siren has a tunable filter with a time constant of 1 second to 600 seconds to prevent wind speed nuisance tripping. The user can choose to display the current value, peak value and average value of the wind speed in MPH, M/S or KPH. In order to obtain high-precision measurement data, the alarm clock is controlled by a crystal oscillator. The C47 uses a microcontroller to measure the frequency of the anemometer signal once per second. This frequency will be calibrated using the user-selected unit of wind speed. The current wind speed drives a digital-to-analog converter that controls the analog output signal of the wind speed. A low-pass filter uses user-entered time constants to process wind speed data. The filtered wind speed signal is compared with various wind speed setting values ​​and the alarm will start when needed. During periods of power up and no wind, the controller checks the continuity of the anemometer circuit by measuring the resistance of the circuit. The optional vane is activated by an adjustable DC voltage. The signal at the tap of the wind blade is proportional to the wind direction measured by an analog to digital converter. This signal is converted to orientation degrees and displayed as needed. The wind vane circuit checks continuity every ten seconds