diff --git a/src/se/hal/struct/Event.java b/src/se/hal/struct/Event.java
index 5fb82de0..9043097f 100755
--- a/src/se/hal/struct/Event.java
+++ b/src/se/hal/struct/Event.java
@@ -2,6 +2,7 @@ package se.hal.struct;
 
 import se.hal.intf.HalEvent;
 import se.hal.intf.HalEventController;
+import se.hal.intf.HalSensor;
 import zutil.db.DBConnection;
 import zutil.db.bean.DBBean;
 import zutil.db.bean.DBBeanSQLResultHandler;
@@ -10,6 +11,9 @@ import zutil.io.StringOutputStream;
 import zutil.log.LogUtil;
 import zutil.parser.json.JSONObjectInputStream;
 import zutil.parser.json.JSONObjectOutputStream;
+import zutil.parser.json.JSONParser;
+import zutil.parser.json.JSONWriter;
+import zutil.ui.Configurator;
 
 import java.io.IOException;
 import java.sql.PreparedStatement;
@@ -49,16 +53,16 @@ public class Event extends DBBean{
 
     public void setEventData(HalEvent eventData){
         this.eventData = eventData;
+        updateConfig();
     }
     public HalEvent getEventData(){
-        if(eventData == null) {
+        if(config !=null && eventData == null) {
             try {
                 Class c = Class.forName(type);
+                eventData = (HalEvent) c.newInstance();
 
-                JSONObjectInputStream in = new JSONObjectInputStream(
-                        new StringInputStream(config));
-                eventData = (HalEvent) in.readObject(c);
-                in.close();
+                Configurator<HalEvent> configurator = new Configurator<>(eventData);
+                configurator.setValues(JSONParser.read(config));
             } catch (Exception e){
                 logger.log(Level.SEVERE, "Unable to read event data", e);
             }
@@ -66,22 +70,16 @@ public class Event extends DBBean{
         return eventData;
     }
     public void save(DBConnection db) throws SQLException {
-        if(eventData != null) {
-            try {
-                StringOutputStream buff = new StringOutputStream();
-                JSONObjectOutputStream out = new JSONObjectOutputStream(buff);
-                out.enableMetaData(false);
-                out.writeObject(eventData);
-                out.close();
-                this.config = buff.toString();
-            } catch (IOException e){
-                logger.log(Level.SEVERE, "Unable to save event data", e);
-            }
-        }
+        if(eventData != null)
+            updateConfig();
         else
             this.config = null;
         super.save(db);
     }
+    private void updateConfig(){
+        Configurator<HalEvent> configurator = new Configurator<>(eventData);
+        this.config = JSONWriter.toString(configurator.getValuesAsNode());
+    }
 
 
     public String getName() {
@@ -94,14 +92,19 @@ public class Event extends DBBean{
         return type;
     }
     public void setType(String type) {
-        this.type = type;
+        if( ! this.type.equals(type)) {
+            this.type = type;
+            this.eventData = null; // invalidate current sensor data object
+        }
     }
     public String getConfig() {
         return config;
     }
     public void setConfig(String config) {
-        this.config = config;
-        this.eventData = null; // invalidate current sensor data object
+        if( ! this.config.equals(config)) {
+            this.config = config;
+            this.eventData = null; // invalidate current sensor data object
+        }
     }
 
     public User getUser() {
diff --git a/src/se/hal/struct/Sensor.java b/src/se/hal/struct/Sensor.java
index 7317178e..a90fbe6d 100755
--- a/src/se/hal/struct/Sensor.java
+++ b/src/se/hal/struct/Sensor.java
@@ -12,6 +12,9 @@ import zutil.io.StringOutputStream;
 import zutil.log.LogUtil;
 import zutil.parser.json.JSONObjectInputStream;
 import zutil.parser.json.JSONObjectOutputStream;
+import zutil.parser.json.JSONParser;
+import zutil.parser.json.JSONWriter;
+import zutil.ui.Configurator;
 
 import java.io.IOException;
 import java.sql.PreparedStatement;
@@ -85,14 +88,13 @@ public class Sensor extends DBBean{
         updateConfig();
 	}
     public HalSensor getSensorData(){
-        if(sensorData == null) {
+        if(config !=null && sensorData == null) {
             try {
                 Class c = Class.forName(type);
+                sensorData = (HalSensor) c.newInstance();
 
-                JSONObjectInputStream in = new JSONObjectInputStream(
-                        new StringInputStream(config));
-                sensorData = (HalSensor) in.readObject(c);
-                in.close();
+                Configurator<HalSensor> configurator = new Configurator<>(sensorData);
+                configurator.setValues(JSONParser.read(config));
             } catch (Exception e){
                 logger.log(Level.SEVERE, "Unable to read sensor data", e);
             }
@@ -107,16 +109,8 @@ public class Sensor extends DBBean{
         super.save(db);
     }
     private void updateConfig(){
-        try {
-            StringOutputStream buff = new StringOutputStream();
-            JSONObjectOutputStream out = new JSONObjectOutputStream(buff);
-            out.enableMetaData(false);
-            out.writeObject(sensorData);
-            out.close();
-            this.config = buff.toString();
-        } catch (IOException e){
-            logger.log(Level.SEVERE, "Unable to save sensor data", e);
-        }
+        Configurator<HalSensor> configurator = new Configurator<>(sensorData);
+        this.config = JSONWriter.toString(configurator.getValuesAsNode());
     }
 
 	
@@ -130,14 +124,19 @@ public class Sensor extends DBBean{
 		return type;
 	}
 	public void setType(String type) {
-		this.type = type;
+		if( ! this.type.equals(type)) {
+			this.type = type;
+			this.sensorData = null; // invalidate current sensor data object
+		}
 	}
 	public String getConfig() {
 		return config;
 	}
 	public void setConfig(String config) {
-		this.config = config;
-        this.sensorData = null; // invalidate current sensor data object
+        if( ! this.config.equals(config)) {
+            this.config = config;
+            this.sensorData = null; // invalidate current sensor data object
+        }
 	}
 
 	public User getUser() {
diff --git a/web-resource/pc_overview.tmpl b/web-resource/pc_overview.tmpl
index b13f9096..4da333be 100755
--- a/web-resource/pc_overview.tmpl
+++ b/web-resource/pc_overview.tmpl
@@ -23,7 +23,7 @@
 				[
 				{ y: (Date.now()-24*60*60*1000) },
 				{{#minData}}  
-					{ y: {{.timestamp}}, {{.username}}: {{.data}} },
+					{ y: {{.timestamp}}, "{{.username}}": {{.data}} },
 				{{/minData}}
 				{ y: Date.now() }
 				]
@@ -32,20 +32,20 @@
 				[
 				{ y: (Date.now()-7*24*60*60*1000) },
 				{{#hourData}}  
-					{ y: {{.timestamp}}, {{.username}}: {{.data}} },  
+					{ y: {{.timestamp}}, "{{.username}}": {{.data}} },
 				{{/hourData}}
 				{ y: Date.now() }
 				]
 		);
 		chartData("day-power-chart", 
 				[{{#dayData}}  
-					{ y: {{.timestamp}}, {{.username}}: {{.data}} },
+					{ y: {{.timestamp}}, "{{.username}}": {{.data}} },
 				{{/dayData}}
 				{ y: Date.now() }
 				]
 		);
 	});
-    var userArray = [ {{#username}} '{{.}}', {{/username}} ];
+    var userArray = [ {{#username}} "{{.}}", {{/username}} ];
     function chartData(elementId, data){
         Morris.Line({
               element: elementId,