Anemometer Pulse, Help!

Using Arduino Programming Questions
1

Hi, I am new here, I just get some problem with my anemometer pulse output which type is QS-FS02, so I just have the code, but I didn't know why Ardunio Mega 2560 can't read the pulse.
there are 3 cable: brown to 5v, black to gnd, blue to pin5.
please Help, there is something wrong in my code?

#include <FreqCounter.h>

float frq;
int freq1;
int pinLed=13;

void setup() {
pinMode(pinLed, OUTPUT);

Serial.begin(9600); // connect to the serial port

Serial.println("Frequency Counter");

}

void loop() {

// wait if any serial is going on
FreqCounter::f_comp=10; // Cal Value / Calibrate with professional Freq Counter
FreqCounter::start(1000); // 1000 ms Gate Time

while (FreqCounter::f_ready == 0)

frq=FreqCounter::f_freq;
Serial.print(" Freq: ");
Serial.println(frq);
freq1=(frq*0.428989)+0.944195;
if(freq1<=0.944195) freq1=0;
Serial.println(freq1);

delay(20);
digitalWrite(pinLed,!digitalRead(pinLed)); // blink Led

}

2

Use code tags, not quote tags, when posting code.

Nowhere does your code read pin 5.

Where did you find the library "FreqCounter" and what is it supposed to do?

3

Sorry, I am new here
I didn't know what suppose to do in FreqCounter.h because I just have it from my friend

4

Appears the power supply is 5, 7, or 12 to 24 volts, that link shows several different output types, voltage, current, RS485, modbus, which ONE do you have? is there a part number in addition to QS-FS02?