diff --git a/OutputConst.h b/OutputConst.h
index efd2358..a4900af 100644
--- a/OutputConst.h
+++ b/OutputConst.h
@@ -60,6 +60,7 @@ static const std::string GVAR_TCOMP = ".TCOMP" ;         // (int)     numero cor
 static const std::string GVAR_TDIAM = ".TDIAM" ;         // (num)     diametro utensile
 static const std::string GVAR_TLEN = ".TLEN" ;           // (num)     lunghezza utensile
 static const std::string GVAR_SMAX = ".SMAX" ;           // (num)     massima speed utensile
+static const std::string GVAR_FIRST = ".FIRST" ;         // (bool)    flag per primo utensile
 static const std::string GVAR_NEXTTOOL = ".NEXTTOOL" ;   // (string)  nome del prossimo utensile
 static const std::string GVAR_NEXTHEAD = ".NEXTHEAD" ;   // (string)  nome testa del prossimo utensile
 static const std::string GVAR_NEXTEXIT = ".NEXTEXIT" ;   // (int)     indice uscita su testa del prox utensile
diff --git a/Simulator.cpp b/Simulator.cpp
index 78b99ca..eacd233 100644
--- a/Simulator.cpp
+++ b/Simulator.cpp
@@ -326,7 +326,7 @@ Simulator::UpdateTool( bool bFirst)
          if ( ! UpdateAxes())
             return false ;
         // eventuale lancio script
-         if ( ! bFirst  &&  ! OnToolSelect( m_sTool, sHead, nExit, sTcPos))
+         if ( ! OnToolSelect( m_sTool, sHead, nExit, sTcPos, bFirst))
             return false ;
       }
       return true ;
@@ -351,7 +351,7 @@ Simulator::UpdateTool( bool bFirst)
       if ( ! UpdateAxes())
          return false ;
      // eventuale lancio script
-      if ( ! bFirst  &&  ! OnToolSelect( m_sTool, sHead, nExit, sTcPos))
+      if ( ! OnToolSelect( m_sTool, sHead, nExit, sTcPos, bFirst))
          return false ;
       return true ;
    }
@@ -482,7 +482,7 @@ Simulator::FindAndManageOperationStart( bool bFirst, int& nStatus)
            // cambio fase
             m_pMchMgr->SetCurrPhase( pDisp->GetPhase()) ;
            // aggiorno utensile e assi conseguenti
-            if ( ! UpdateTool()) {
+            if ( ! UpdateTool( bFirst)) {
                nStatus = MCH_SIM_ERR ;
                return false ;
             }
@@ -855,7 +855,8 @@ Simulator::OnDispositionEnd( void)
 
 //----------------------------------------------------------------------------
 bool
-Simulator::OnToolSelect( const string& sTool, const string& sHead, int nExit, const string& sTcPos)
+Simulator::OnToolSelect( const string& sTool, const string& sHead, int nExit, const string& sTcPos,
+                         bool bFirst)
 {
   // assegno il nome dell'utensile, la testa e l'uscita
    if ( ! m_pMachine->LuaSetGlobVar( GLOB_VAR + GVAR_TOOL, sTool)  ||
@@ -877,6 +878,9 @@ Simulator::OnToolSelect( const string& sTool, const string& sHead, int nExit, co
             return false ;
       }
    }
+  // assegno il flag di chiamata di utensile iniziale
+   if ( ! m_pMachine->LuaSetGlobVar( GLOB_VAR + GVAR_FIRST, bFirst))
+      return false ;
   // verifico esistenza funzione
    if ( ! m_pMachine->LuaExistsFunction( ON_SIMUL_TOOL_SELECT))
       return true ;
diff --git a/Simulator.h b/Simulator.h
index 7e50c39..9eaaf24 100644
--- a/Simulator.h
+++ b/Simulator.h
@@ -56,7 +56,7 @@ class Simulator
       bool OnDispositionStart( int nOpId, int nOpInd, int nPhase,
                                const std::string& sTable, const Point3d& ptOri1, bool bEmpty) ;
       bool OnDispositionEnd( void) ;
-      bool OnToolSelect( const std::string& sTool, const std::string& sHead, int nExit, const std::string& sTcPos) ;
+      bool OnToolSelect( const std::string& sTool, const std::string& sHead, int nExit, const std::string& sTcPos, bool bFirst) ;
       bool OnToolDeselect( const std::string& sNextTool, const std::string& sNextHead, int nNextExit, const std::string& sNextTcPos) ;
       bool OnMachiningStart( int nOpId, int nOpInd) ;
       bool OnMachiningEnd( void) ;