diff --git a/qgroundcontrol.pro b/qgroundcontrol.pro
index 9ccffa873a306558b731b48706df0a78d74007e2..de1f54a8d5aa3fa1f65e748d3e25ccfaf81061e5 100644
--- a/qgroundcontrol.pro
+++ b/qgroundcontrol.pro
@@ -226,6 +226,8 @@ RESOURCES = mavground.qrc
 
 # Include RT-LAB Library
 win32 { 
+exists(src/lib/opalrt/OpalApi.h){
+    message("Building support for Opal-RT")
     LIBS += -LC:\OPAL-RT\RT-LAB7.2.4\Common\bin \
         -lOpalApi
     INCLUDEPATH += src/lib/opalrt
@@ -240,3 +242,4 @@ win32 {
         src/comm/ParameterList.h
     DEFINES += OPAL_RT
 }
+}
diff --git a/src/comm/ParameterList.cc b/src/comm/ParameterList.cc
index 9c7d2430a22de7b23b77116de4e306121837b4a5..6956f83c14e6a5854f7bcbb848a4195bcc027bcf 100644
--- a/src/comm/ParameterList.cc
+++ b/src/comm/ParameterList.cc
@@ -75,7 +75,7 @@ ParameterList::const_iterator::const_iterator()
 
 }
 
-ParameterList::begin()
+const_iterator ParameterList::begin()
 {
 
 }
diff --git a/src/comm/ParameterList.h b/src/comm/ParameterList.h
index 42ca2edfddecdcbeabc77536a17841b3da1392db..2be6485f5d5929b1ebb5d4f6343418b4a8ff4888 100644
--- a/src/comm/ParameterList.h
+++ b/src/comm/ParameterList.h
@@ -41,23 +41,24 @@ namespace OpalRT
 {
     class ParameterList
     {
+    public:
+
         class const_iterator
         {
         public:
             const_iterator();
+            const_iterator(const_iterator& other);
         private:
-            QMap<int, QMap<QGCParamID, Parameter> >::const_iterator componentIter;
-            QMap<QGCParamID, Parameter>::const_iterator paramIter;
+            int componentID;
+            QGCParamID paramID;
         };
-
-    public:
         ParameterList();
         ~ParameterList();
         int setValue(int compid, QGCParamID paramid, float value);
         float getValue(int compid, QGCParamID paramid);
 
-        const_iterator begin() const;
-        const_iterator end() const;
+//        const_iterator begin() const;
+//        const_iterator end() const;
     protected:
         QMap<int, QMap<QGCParamID, Parameter> > *params;