--- a/FXAnalyse.c	Wed Oct 03 15:11:35 2012 +0200
+++ b/FXAnalyse.c	Fri Oct 05 12:53:39 2012 +0200
@@ -139,6 +139,7 @@
 	SLOPE_REFERENCE_HG_CAVITY = 1,
 };
 
+int invertSlopeSign = 0;
 int slopeReference = SLOPE_REFERENCE_MICROWAVE;
 
 volatile bool KeepCentering=FALSE; 
@@ -150,6 +151,8 @@
 
 int DDSFox_Set(DDSParameter *DDS, double Frequency, double Sweeprate)
 {
+	printf("DDSFox_Set(Frequency=%g, Sweeprate=%g)\n", Frequency, Sweeprate);
+	
 	DDS->Frequency = Frequency; 
 	DDS->SweepRate = Sweeprate;
 	
@@ -1274,11 +1277,16 @@
 							{
 								Nratio = Nratio + 1;
 								
-								if (Nratio >= 1)
-								{
+								if (Nratio >= 1) {
 									MoyMath2 = MoyMath2 + Moy_Math2slope;
 								}
-								SlopeMath2 = SlopeMath2 + Slope_Math2slope;
+								
+								if (invertSlopeSign) {
+									SlopeMath2 = SlopeMath2 - Slope_Math2slope;
+								} else {
+									SlopeMath2 = SlopeMath2 + Slope_Math2slope;
+								}
+								
 								N_Math2slope = 0.0;
 								Math2_slope = 0.0;
 								Moy_Math2slope = 0.0;
@@ -1292,8 +1300,6 @@
 
 								OnSlopeCancelling = TRUE;
 								
-								FoxFrequ = DDSFox_ReadFreq(&DDS1xAD9956);
-								
 								if (Nratio == ratio)
 								{
 									if (FrequCorrec == TRUE)
@@ -1305,6 +1311,7 @@
 									MoyMath2 = 0.0;
 								}
 								
+								FoxFrequ = DDSFox_ReadFreq(&DDS1xAD9956);
 								SetCtrlVal(MainPanel, PANEL_SLOPETOCANCEL, SlopeMath2);
 								DDSFox_Set(&DDS1xAD9956, FoxFrequ, SlopeMath2);
 								
@@ -1440,14 +1447,11 @@
 						
 						// Special case to handle change of day at next second
 						if ( LocalTime.tm_hour==23 && LocalTime.tm_min==59 && strtod(Sec,NULL)>=58 ) { 
-							printf("Entering change of date substructure\r\n"); 
-							printf("old file : %s %s %s \r\n",Date, Time, LogFileName);
 							Acquiring = FALSE ;
 							do {
 								Delay(5.1);
 								CurrentFileName(LogFileName) ;
 							} while (!GetFileInfo(LogFileName, &OldLogFilePtr));
-							printf("new file : %s \r\n\r\n",Date, Time, LogFileName);  
 							Acquiring = TRUE ;
 							OldLogFilePtr = 2;
 						}
@@ -2586,3 +2590,15 @@
 	}
 	return 0;
 }
+
+int CVICALLBACK CB_InvertSlopeSign (int panel, int control, int event,
+		void *callbackData, int eventData1, int eventData2)
+{
+	switch (event)
+	{
+		case EVENT_COMMIT:
+			GetCtrlVal(panel, control, &invertSlopeSign);
+			break;
+	}
+	return 0;
+}