const byte PotiSignalPin = A0;

// easy to use helper-function for non-blocking timing
boolean TimePeriodIsOver (unsigned long &startOfPeriod, unsigned long TimePeriod) {
  unsigned long currentMillis  = millis();
  if ( currentMillis - startOfPeriod >= TimePeriod ) {
    // more time than TimePeriod has elapsed since last time if-condition was true
    startOfPeriod = currentMillis; // a new period starts right here so set new starttime
    return true;
  }
  else return false;            // actual TimePeriod is NOT yet over
}

unsigned long myTimer;
int ADC_Value;

void setup() {
  Serial.begin(115200); // adjust baudrate in the serial-monitor to 115200 too
  Serial.println("Setup-Start");
  //pinMode(PotiSignalPin, INPUT); // defining an analoginput-pin is not nescessary
  myTimer = millis(); // store actual timestamp of function millis() 
}



void loop() {
  ADC_Value = analogRead(PotiSignalPin);

  // non-blocking timing: compare how much time has passed by
  if ( TimePeriodIsOver (myTimer,500) ) { // check if 500 milliseconds have passed by
    // if 500 milliseconds HAVE passed by
    Serial.print("Value from ADC-input is:");
    Serial.println(ADC_Value);
  }
}