void increaseCounter(byte _cNum) {
  unsigned long _deltaTime;
  unsigned long _currMillis;

  _currMillis = millis();
  _deltaTime = _currMillis - pulseInLastMillis[_cNum];
  pulseInLastMillis[_cNum] = _currMillis;

  currentReadingImpulses[_cNum]++;
  if (currentReadingImpulses[_cNum] >= meter_impPerUnit[_cNum]) {
    currentReading[_cNum]++;
    currentReadingImpulses[_cNum] = 0;
    storeCurrentReading(_cNum, false);
  }
  printCurrentReading(_cNum, _deltaTime, true);
}


void printCurrentReadings() {
  for (byte i = 0; i < COUNTERS_COUNT; i++) {
    printCurrentReading(i, 0, false);
  }
}

void printCurrentReading(byte _cNum, unsigned long _deltaTime, bool _sendDeltaTime) {
  if (output_json) {
    Serial.print(F("{\"C\":"));
    Serial.print(_cNum + 1);
    Serial.print(F(", \"reading\":"));
    Serial.print(currentReading[_cNum]);
    Serial.print(".");
    if (meter_impPerUnit[_cNum] == 100 && currentReadingImpulses[_cNum] < 10) Serial.print("0");
    else if (meter_impPerUnit[_cNum] == 1000 && currentReadingImpulses[_cNum] < 10) Serial.print("00");
    else if (meter_impPerUnit[_cNum] == 1000 && currentReadingImpulses[_cNum] < 100) Serial.print("0");
    Serial.print(currentReadingImpulses[_cNum]);

    Serial.print(F(", \"impPerU\":"));
    Serial.print(meter_impPerUnit[_cNum]);
      
    if (_sendDeltaTime) {
      Serial.print(F(", \"dTime\":"));
      Serial.print(_deltaTime);
    }
    Serial.println("}");
  }
  else {
    Serial.print("C");
    Serial.print(_cNum + 1);
    Serial.print("=");
    Serial.print(currentReading[_cNum]);
    Serial.print(".");
    if (meter_impPerUnit[_cNum] == 100 && currentReadingImpulses[_cNum] < 10) Serial.print("0");
    else if (meter_impPerUnit[_cNum] == 1000 && currentReadingImpulses[_cNum] < 10) Serial.print("00");
    else if (meter_impPerUnit[_cNum] == 1000 && currentReadingImpulses[_cNum] < 100) Serial.print("0");
    Serial.print(currentReadingImpulses[_cNum]);
    Serial.print(";");
    Serial.print(meter_impPerUnit[_cNum]);
    if (_sendDeltaTime) {
      Serial.print(";");
      Serial.print(_deltaTime);
    }
    Serial.println();
  }
  lastDataSent_seconds[_cNum] = seconds;
}



void onNoImpulseTimeout() {
  for (byte i = 0; i < COUNTERS_COUNT; i++) {
    if (meter_noImpulseTimeout_seconds[i] > 0) {
      bool _sendDataNow = false;
      
      // store counter to EEPROM if value changed
      if ( (currentReadingImpulses_saved[i] != currentReadingImpulses[i]) && ((millis() - pulseInLastMillis[i]) >= (meter_noImpulseTimeout_seconds[i] * 1000)) ) {
        currentReadingImpulses_saved[i] = currentReadingImpulses[i];
        storeCurrentImpulses(i, false);
        Serial.print(F("INFO: saved impCount C"));
        Serial.print(i + 1);
        Serial.print(F(" (noImpTout)"));
        Serial.println();
        _sendDataNow = true;
      }


      // send current data with current usage=0 on interval
      if ( _sendDataNow || (seconds - lastDataSent_seconds[i]) >= meter_noImpulseTimeout_seconds[i] ) {
        if(debug) {
          Serial.print(F("send data on noImpTout C"));
          Serial.print(i + 1);
          Serial.print("(");
          Serial.print(meter_noImpulseTimeout_seconds[i]);
          Serial.println("s)");
        }
        printCurrentReading(i, 0, true);
        lastDataSent_seconds[i] = seconds;
      }
    }
  }
}



void saveDataOnInterval() {
  for (byte i = 0; i < COUNTERS_COUNT; i++) {
    if (meter_savePulsesOnInterval_mins[i] > 0 && (currentReadingImpulses_saved[i] != currentReadingImpulses[i])) {
      if ((seconds - pulsesLastSaved_seconds[i]) >= (meter_savePulsesOnInterval_mins[i] * 60)) {
        storeCurrentImpulses(i, false);
        pulsesLastSaved_seconds[i] = seconds;
        Serial.print(F("INFO: saved impCount C"));
        Serial.print(i + 1);
        Serial.print(F(" (fixed interval)"));
        Serial.println();
      }
    }
  }
}



/*void printImpPerUnit(byte _cNum) {
  Serial.print("C");
  Serial.print(_cNum + 1);
  Serial.print(F(": imp/unit="));
  Serial.println(meter_impPerUnit[_cNum]);
}*/