   analogWrite(kFan0PwmPin, map(fan_0_dutycycle,0,100,0,255));
   analogWrite(kFan1PwmPin, map(fan_1_dutycycle,0,100,0,255));
   analogWrite(kFan2PwmPin, map(fan_2_dutycycle,0,100,0,255));
+  analogWrite(kFan3PwmPin, map(fan_3_dutycycle,0,100,0,255));
 
   delay(200);
 }

  Serial.print(",");
  Serial.print(rpm2);
  Serial.print(",");
  Serial.print(fan_0_dutycycle);
  Serial.print(",");
  Serial.print(fan_1_dutycycle);
  Serial.print(",");
  Serial.println(fan_2_dutycycle);

  if (ReadSerial(command, kCommandLength)) {
    switch (command[0]) {

  const int kCommandSetDutycycle = 1;
  const int kCommandSetDefaultDutycycle = 2;
  
  unsigned int rpm0, rpm1, rpm2, rpm3;

  rpm0 = ReadRpm(kFan0RpmPin);
  rpm1 = ReadRpm(kFan1RpmPin);
  rpm2 = ReadRpm(kFan2RpmPin);
  rpm3 = ReadRpm(kFan3RpmPin);
      
  Serial.print(rpm0);
  Serial.print(",");
