void loop() {
  counter++;
 // Serial.println(counter);
  if (counter <=1)  messung();
  }

void messung() {
  float u2=analogRead(14)*4.8875;
  float u3=analogRead(15)*4.8875;
  float u4=analogRead(16)*4.8875;
  float u5=analogRead(17)*4.8875;
  float u6=analogRead(18)*4.8875;

  Serial.print("UC2 = ");
  Serial.println(u2);
  Serial.print("UC3 = ");
  Serial.println(u3);
  Serial.print("UC4 = ");
  Serial.println(u4);
  Serial.print("UC5 = ");
  Serial.println(u5);
  Serial.print("UC6 = ");
  Serial.println(u6);
}