--- a/FXAnalyse.c	Tue Jul 03 12:27:45 2012 +0200
+++ b/FXAnalyse.c	Tue Jul 03 13:11:40 2012 +0200
@@ -160,8 +160,12 @@
 
 double limitotakoff=70.0;
 
+enum {
+	SLOPE_REFERENCE_MICROWAVE = 0,
+	SLOPE_REFERENCE_HG_CAVITY = 1,
+};
 
-
+int slopeReference = SLOPE_REFERENCE_MICROWAVE;
 
 //////////////////////////////////
 //  Keep Centered Variables
@@ -634,7 +638,7 @@
 					
 					if (LogFileSize > OldLogFilePtr+2*FXLINELENGTH-2) {  // if a complete newline has been written
 						
-						SuspendTimerCallbacks ; 
+						SuspendTimerCallbacks() ; 
 						
 						// Open Log file and get to the beginning of newly completed line
 						LogFile = OpenFile(LogFileName, VAL_READ_ONLY, VAL_OPEN_AS_IS, VAL_ASCII) ;
@@ -1296,6 +1300,18 @@
 						
 						if (SlopeMeasuring == TRUE)
 						{
+							double currentFreq;
+							
+							/* select reference */
+							switch (slopeReference) {
+								case SLOPE_REFERENCE_MICROWAVE:
+									currentFreq = Math2;
+									break;
+								case SLOPE_REFERENCE_HG_CAVITY:
+									currentFreq = Math3;
+									break;
+							}
+							
 							if  (utc-SlopeMeasuringTimeBegin > TimetoSlope)
 							{
 								Nratio = Nratio + 1;
@@ -1343,14 +1359,14 @@
 								if (nstabilisationSlopeMeasuring < 5)
 								{
 									nstabilisationSlopeMeasuring = nstabilisationSlopeMeasuring + 1;
-									Math2_slope = Math2; 
+									Math2_slope = currentFreq; 
 								}
 								else
 								{
-									if ((Math2-Math2_slope) < limitotakoff && (Math2-Math2_slope) > -limitotakoff)
+									if ((currentFreq-Math2_slope) < limitotakoff && (currentFreq-Math2_slope) > -limitotakoff)
 									{
 										N_Math2slope = N_Math2slope + 1;
-										Math2_slope = Math2;
+										Math2_slope = currentFreq;
 										Moy_Math2slope = ((N_Math2slope-1)*Moy_Math2slope + Math2_slope)/N_Math2slope;
 										Slope_Math2slope = (Slope_Math2slope*(N_Math2slope-2) + 6*(Math2_slope-Moy_Math2slope)/N_Math2slope)/(N_Math2slope+1) ;
 									}
@@ -1540,7 +1556,7 @@
 							OldLogFilePtr = 2;
 							}
 						
-						ResumeTimerCallbacks ; 
+						ResumeTimerCallbacks() ; 
 						
 						} ;
 					
@@ -2870,3 +2886,15 @@
 		}
 	return 0;
 }
+
+int CVICALLBACK SlopeReference_cb (int panel, int control, int event,
+		void *callbackData, int eventData1, int eventData2)
+{
+	switch (event)
+	{
+		case EVENT_COMMIT:
+			GetCtrlVal(MainPanel, PANEL_SLOPE_REFERENCE, &slopeReference);
+			break;
+	}
+	return 0;
+}