diff --git a/src/FactSystem/Fact.cc b/src/FactSystem/Fact.cc
index d43488fa5959eb5ddc311661098ba6b11c03c3fa..a69b25831813093008c547a51e3f297f7fe245f3 100644
--- a/src/FactSystem/Fact.cc
+++ b/src/FactSystem/Fact.cc
@@ -134,7 +134,7 @@ QString Fact::valueString(void) const
     return _value.toString();
 }
 
-QVariant Fact::defaultValue(void)
+QVariant Fact::defaultValue(void) const
 {
     if (_metaData) {
         if (!_metaData->defaultValueAvailable()) {
@@ -147,12 +147,12 @@ QVariant Fact::defaultValue(void)
     }
 }
 
-FactMetaData::ValueType_t Fact::type(void)
+FactMetaData::ValueType_t Fact::type(void) const
 {
     return _type;
 }
 
-QString Fact::shortDescription(void)
+QString Fact::shortDescription(void) const
 {
     if (_metaData) {
         return _metaData->shortDescription();
@@ -162,7 +162,7 @@ QString Fact::shortDescription(void)
     }
 }
 
-QString Fact::longDescription(void)
+QString Fact::longDescription(void) const
 {
     if (_metaData) {
         return _metaData->longDescription();
@@ -172,7 +172,7 @@ QString Fact::longDescription(void)
     }
 }
 
-QString Fact::units(void)
+QString Fact::units(void) const
 {
     if (_metaData) {
         return _metaData->units();
@@ -182,7 +182,7 @@ QString Fact::units(void)
     }
 }
 
-QVariant Fact::min(void)
+QVariant Fact::min(void) const
 {
     if (_metaData) {
         return _metaData->min();
@@ -192,7 +192,7 @@ QVariant Fact::min(void)
     }
 }
 
-QVariant Fact::max(void)
+QVariant Fact::max(void) const
 {
     if (_metaData) {
         return _metaData->max();
@@ -202,7 +202,7 @@ QVariant Fact::max(void)
     }
 }
 
-bool Fact::minIsDefaultForType(void)
+bool Fact::minIsDefaultForType(void) const
 {
     if (_metaData) {
         return _metaData->minIsDefaultForType();
@@ -212,7 +212,7 @@ bool Fact::minIsDefaultForType(void)
     }
 }
 
-bool Fact::maxIsDefaultForType(void)
+bool Fact::maxIsDefaultForType(void) const
 {
     if (_metaData) {
         return _metaData->maxIsDefaultForType();
@@ -222,7 +222,7 @@ bool Fact::maxIsDefaultForType(void)
     }
 }
 
-QString Fact::group(void)
+QString Fact::group(void) const
 {
     if (_metaData) {
         return _metaData->group();
@@ -237,7 +237,7 @@ void Fact::setMetaData(FactMetaData* metaData)
     _metaData = metaData;
 }
 
-bool Fact::valueEqualsDefault(void)
+bool Fact::valueEqualsDefault(void) const
 {
     if (_metaData) {
         if (_metaData->defaultValueAvailable()) {
@@ -251,7 +251,7 @@ bool Fact::valueEqualsDefault(void)
     }
 }
 
-bool Fact::defaultValueAvailable(void)
+bool Fact::defaultValueAvailable(void) const
 {
     if (_metaData) {
         return _metaData->defaultValueAvailable();
diff --git a/src/FactSystem/Fact.h b/src/FactSystem/Fact.h
index 90be94d4a41d842b045a899633ff8adbdda4c844..da8a85efebd290f8e8ffc5f1ea16ce1085354358 100644
--- a/src/FactSystem/Fact.h
+++ b/src/FactSystem/Fact.h
@@ -74,18 +74,18 @@ public:
     QVariant value(void) const;
     QString valueString(void) const;
     void setValue(const QVariant& value);
-    QVariant defaultValue(void);
-	bool defaultValueAvailable(void);
-    bool valueEqualsDefault(void);
-    FactMetaData::ValueType_t type(void);
-    QString shortDescription(void);
-    QString longDescription(void);
-    QString units(void);
-    QVariant min(void);
-    bool minIsDefaultForType(void);
-    QVariant max(void);    
-    bool maxIsDefaultForType(void);
-    QString group(void);
+    QVariant defaultValue(void) const;
+	bool defaultValueAvailable(void) const;
+    bool valueEqualsDefault(void) const;
+    FactMetaData::ValueType_t type(void) const;
+    QString shortDescription(void) const;
+    QString longDescription(void) const;
+    QString units(void) const;
+    QVariant min(void) const;
+    bool minIsDefaultForType(void) const;
+    QVariant max(void) const;
+    bool maxIsDefaultForType(void) const;
+    QString group(void) const;
     
     /// Sets and sends new value to vehicle even if value is the same
     void forceSetValue(const QVariant& value);
@@ -120,4 +120,4 @@ private:
     FactMetaData*               _metaData;
 };
 
-#endif
\ No newline at end of file
+#endif
diff --git a/src/FactSystem/FactMetaData.cc b/src/FactSystem/FactMetaData.cc
index 3d63c41c944272fbca43957f0ff143ce1d7462bd..7360e65a7912a0417476a8d8dbc59c8bf2d7704a 100644
--- a/src/FactSystem/FactMetaData.cc
+++ b/src/FactSystem/FactMetaData.cc
@@ -80,7 +80,7 @@ const FactMetaData& FactMetaData::operator=(const FactMetaData& other)
     return *this;
 }
 
-QVariant FactMetaData::defaultValue(void)
+QVariant FactMetaData::defaultValue(void) const
 {
     if (_defaultValueAvailable) {
         return _defaultValue;
@@ -122,7 +122,7 @@ void FactMetaData::setMax(const QVariant& max)
     }
 }
 
-QVariant FactMetaData::_minForType(void)
+QVariant FactMetaData::_minForType(void) const
 {
     switch (_type) {
         case valueTypeUint8:
@@ -147,7 +147,7 @@ QVariant FactMetaData::_minForType(void)
     return QVariant();
 }
 
-QVariant FactMetaData::_maxForType(void)
+QVariant FactMetaData::_maxForType(void) const
 {
     switch (_type) {
         case valueTypeUint8:
diff --git a/src/FactSystem/FactMetaData.h b/src/FactSystem/FactMetaData.h
index 8ad7c11182404e87f6667791b2257fec12fe5626..49c72d8784332c2a3e4ad27ac79f2af15a7cbe86 100644
--- a/src/FactSystem/FactMetaData.h
+++ b/src/FactSystem/FactMetaData.h
@@ -57,28 +57,28 @@ public:
     FactMetaData(const FactMetaData& other, QObject* parent = NULL);
 
     const FactMetaData& operator=(const FactMetaData& other);
-    
-	// Property accessors
-    QString     name(void)                      { return _name; }
-	QString     group(void)						{ return _group; }
-	ValueType_t type(void)                      { return _type; }
-	QVariant    defaultValue(void);
-	bool		defaultValueAvailable(void)     { return _defaultValueAvailable; }
-	QString     shortDescription(void)          { return _shortDescription; }
-	QString     longDescription(void)           { return _longDescription;}
-	QString     units(void)                     { return _units; }
-	QVariant    min(void)                       { return _min; }
-	QVariant    max(void)                       { return _max; }
-    bool        minIsDefaultForType(void)       { return _minIsDefaultForType; }
-    bool        maxIsDefaultForType(void)       { return _maxIsDefaultForType; }
-	
-	// Property setters
+
+    // Property accessors
+    QString     name(void) const                  { return _name; }
+    QString     group(void) const                 { return _group; }
+    ValueType_t type(void) const                  { return _type; }
+    QVariant    defaultValue(void) const;
+    bool		defaultValueAvailable(void) const { return _defaultValueAvailable; }
+    QString     shortDescription(void) const      { return _shortDescription; }
+    QString     longDescription(void) const       { return _longDescription;}
+    QString     units(void) const                 { return _units; }
+    QVariant    min(void) const                   { return _min; }
+    QVariant    max(void) const                   { return _max; }
+    bool        minIsDefaultForType(void) const   { return _minIsDefaultForType; }
+    bool        maxIsDefaultForType(void) const   { return _maxIsDefaultForType; }
+
+    // Property setters
     void setName(const QString& name)                           { _name = name; }
-	void setGroup(const QString& group)                         { _group = group; }
-	void setDefaultValue(const QVariant& defaultValue);
-	void setShortDescription(const QString& shortDescription)   { _shortDescription = shortDescription; }
-	void setLongDescription(const QString& longDescription)     { _longDescription = longDescription;}
-	void setUnits(const QString& units)                         { _units = units; }
+    void setGroup(const QString& group)                         { _group = group; }
+    void setDefaultValue(const QVariant& defaultValue);
+    void setShortDescription(const QString& shortDescription)   { _shortDescription = shortDescription; }
+    void setLongDescription(const QString& longDescription)     { _longDescription = longDescription;}
+    void setUnits(const QString& units)                         { _units = units; }
     void setMin(const QVariant& max);
     void setMax(const QVariant& max);
     
@@ -91,8 +91,8 @@ public:
     bool convertAndValidate(const QVariant& value, bool convertOnly, QVariant& typedValue, QString& errorString);
 
 private:
-    QVariant _minForType(void);
-    QVariant _maxForType(void);
+    QVariant _minForType(void) const;
+    QVariant _maxForType(void) const;
     
     QString     _name;
     QString     _group;
@@ -108,4 +108,4 @@ private:
     bool        _maxIsDefaultForType;
 };
 
-#endif
\ No newline at end of file
+#endif