diff --git a/backend/lib/Interpreter/AggregatorInterpreter.php b/backend/lib/Interpreter/AggregatorInterpreter.php
index 267e45d..1f4b03f 100644
--- a/backend/lib/Interpreter/AggregatorInterpreter.php
+++ b/backend/lib/Interpreter/AggregatorInterpreter.php
@@ -36,12 +36,14 @@ use Volkszaehler\Model;
  * @package default
  *
  */
-class AggregatorInterpreter {
+class AggregatorInterpreter implements InterpreterInterface {
 	/**
 	 * @var array of Interpreter
 	 */
 	protected $channelInterpreter = array();
 
+	protected $aggregator;
+
 	/**
 	 * Constructor
 	 *
@@ -53,13 +55,14 @@ class AggregatorInterpreter {
 	 */
 	public function __construct(Model\Aggregator $aggregator, ORM\EntityManager $em, $from, $to) {
 		$indicator = NULL;
+		$this->aggregator = $aggregator;
 
-		foreach ($aggregator->getChannels() as $channels) {
-			if (isset($indicator) && $indicator != $channel->getIndicator()) {
+		foreach ($aggregator->getChannels() as $channel) {
+			if (isset($indicator) && $indicator != $channel->getType()) {
 				throw new \Exception('Can\'t aggregate entities of mixed types!');
 			}
 			else {
-				$indicator = $channel->getIndicator();
+				$indicator = $channel->getType();
 			}
 
 			$this->channelInterpreter[] = $channel->getInterpreter($em, $from, $to);
@@ -77,6 +80,13 @@ class AggregatorInterpreter {
 
 	}
 
+	/**
+	 * @todo to be implemented
+	 */
+	public function getConsumption() {
+
+	}
+
 	/**
 	 * Just a passthrough to the channel interpreters
 	 *
@@ -122,4 +132,9 @@ class AggregatorInterpreter {
 		}
 		return ($sum / count($this->channelInterpreter));
 	}
+
+	/*
+	 * Getter & setter
+	 */
+	public function getUuid() { return $this->aggregator->getUuid(); }
 }
\ No newline at end of file
diff --git a/backend/lib/Interpreter/Interpreter.php b/backend/lib/Interpreter/Interpreter.php
index 9e36054..042aa87 100644
--- a/backend/lib/Interpreter/Interpreter.php
+++ b/backend/lib/Interpreter/Interpreter.php
@@ -30,18 +30,9 @@ namespace Volkszaehler\Interpreter;
  *
  */
 use Volkszaehler\Iterator;
-
 use Volkszaehler;
-
 use Doctrine\ORM\Query;
 
-interface InterpreterInterface {
-	function getConsumption();
-	function getValues();
-	function getMin();
-	function getMax();
-	function getAverage();
-}
 
 /**
  * Interpreter superclass for all interpreters
@@ -183,6 +174,11 @@ abstract class Interpreter implements InterpreterInterface {
 
 		return $sql;
 	}
+
+	/*
+	 * Getter & setter
+	 */
+	public function getUuid() { return $this->channel->getUuid(); }
 }
 
 ?>
\ No newline at end of file
diff --git a/backend/lib/Interpreter/InterpreterInterface.php b/backend/lib/Interpreter/InterpreterInterface.php
new file mode 100644
index 0000000..6e79fa1
--- /dev/null
+++ b/backend/lib/Interpreter/InterpreterInterface.php
@@ -0,0 +1,37 @@
+<?php
+/**
+ * @copyright Copyright (c) 2010, The volkszaehler.org project
+ * @package default
+ * @license http://www.opensource.org/licenses/gpl-license.php GNU Public License
+ */
+/*
+ * This file is part of volkzaehler.org
+ *
+ * volkzaehler.org is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * any later version.
+ *
+ * volkzaehler.org is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with volkszaehler.org. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace Volkszaehler\Interpreter;
+
+/**
+ *
+ * @author Steffen Vogel <info@steffenvogel.de>
+ *
+ */
+interface InterpreterInterface {
+	function getConsumption();
+	function getValues();
+	function getMin();
+	function getMax();
+	function getAverage();
+}
\ No newline at end of file
diff --git a/backend/lib/Interpreter/MeterInterpreter.php b/backend/lib/Interpreter/MeterInterpreter.php
index 7e65396..adc0cf7 100644
--- a/backend/lib/Interpreter/MeterInterpreter.php
+++ b/backend/lib/Interpreter/MeterInterpreter.php
@@ -54,7 +54,7 @@ class MeterInterpreter extends Interpreter {
 	}
 
 	/**
-	 *
+	 * @return array (0 => timestamp, 1 => value)
 	 */
 	public function getMin() {
 		$data = $this->getData();
@@ -69,7 +69,7 @@ class MeterInterpreter extends Interpreter {
 	}
 
 	/**
-	 * @return array
+	 * @return array (0 => timestamp, 1 => value)
 	 */
 	public function getMax() {
 		$data = $this->getData();
@@ -84,7 +84,6 @@ class MeterInterpreter extends Interpreter {
 	}
 
 	/**
-	 * @todo calculate timeinterval if no params were given
 	 * @return float
 	 */
 	public function getAverage() {
@@ -93,6 +92,8 @@ class MeterInterpreter extends Interpreter {
 
 	/**
 	 * Just a passthrough of raw data
+	 *
+	 * @deprecated
 	 */
 	public function getPulses($groupBy = NULL) {
 		return parent::getData($groupBy);
@@ -131,8 +132,8 @@ class MeterInterpreter extends Interpreter {
 		$delta = $next[0] - $last[0];
 
 		return array(
-			($next[0] - $delta / 2),												// timestamp
-			$next[1] * (3600000 / (($this->channel->getProperty('resolution')->getValue() / 1000) * $delta)),	// value
+			($next[0] - $delta / 2),	// timestamp
+			$next[1] * (3600000 / (($this->channel->getProperty('resolution') / 1000) * $delta)),	// value
 			(isset($next[2])) ? $next[2] : 1
 		);
 	}
diff --git a/backend/lib/Interpreter/SensorInterpreter.php b/backend/lib/Interpreter/SensorInterpreter.php
index 53bcb80..b8c0d4c 100644
--- a/backend/lib/Interpreter/SensorInterpreter.php
+++ b/backend/lib/Interpreter/SensorInterpreter.php
@@ -53,7 +53,7 @@ class SensorInterpreter extends Interpreter {
 	/**
 	 * @todo adapt to doctrine orm
 	 * @todo untested
-	 * @return array
+	 * @return array (0 => timestamp, 1 => value)
 	 */
 	public function getMin() {
 		return $this->dbh->query('SELECT value, timestamp FROM data WHERE channel_id = ' . (int) $this->id . self::buildFilterTime($this->from, $this->to) . ' ORDER BY value ASC', 1)->current();
@@ -62,7 +62,7 @@ class SensorInterpreter extends Interpreter {
 	/**
 	 * @todo adapt to doctrine orm
 	 * @todo untested
-	 * @return array
+	 * @return array (0 => timestamp, 1 => value)
 	 */
 	public function getMax() {
 		return $this->dbh->query('SELECT value, timestamp FROM data WHERE channel_id = ' . (int) $this->id . self::buildFilterTime($this->from, $this->to) . ' ORDER BY value DESC', 1)->current();
@@ -79,6 +79,7 @@ class SensorInterpreter extends Interpreter {
 
 	/**
 	 * @todo to be implemented
+	 * @todo possible and/or required?
 	 * @return float
 	 */
 	public function getConsumption() {