#include <Servo.h>

Servo myServo;

const int servoPin = 27;

void setup() {
  myServo.attach(servoPin, 500, 2400);  // complete range
}

void loop() {

  myServo.write(0);    // extrem 1
  delay(2000);

  myServo.write(90);   // center
  delay(2000);

  myServo.write(180);  // extrem 2
  delay(2000);
}