Index: trunk/ppTranslate/src/ppMops.h
===================================================================
--- trunk/ppTranslate/src/ppMops.h	(revision 29565)
+++ trunk/ppTranslate/src/ppMops.h	(revision 29567)
@@ -10,4 +10,6 @@
 #define SOURCE_MASK (PM_SOURCE_MODE_FAIL | PM_SOURCE_MODE_BADPSF | PM_SOURCE_MODE_SATURATED | \
                      PM_SOURCE_MODE_CR_LIMIT | PM_SOURCE_MODE_SKY_FAILURE) // Flags to exclude
+
+#define PS1_DV_FORMAT "PS1_DV%d"
 
 // Configuration data
Index: trunk/ppTranslate/src/ppMopsArguments.c
===================================================================
--- trunk/ppTranslate/src/ppMopsArguments.c	(revision 29565)
+++ trunk/ppTranslate/src/ppMopsArguments.c	(revision 29567)
@@ -17,5 +17,23 @@
     fprintf(stderr, "Usage: %s INPUT_LIST OUTPUT_NAME\n", program);
     fprintf(stderr, "\n");
+    fprintf(stderr, "Description: Merge detections from INPUT_LIST into the single OUTPUT_NAME file\n");
+    fprintf(stderr, "\n");
+    fprintf(stderr, "\tIf the CMF input files have different versions, \n\
+\tmerging cannot be performed.\n");
+    fprintf(stderr, "\n");
+    fprintf(stderr, "\tIf -version option is not given, the output version is\n\
+\tthe version of the input file(s) otherwise the output version is (possibly forced to)\n\
+\tthe version option.\n");
+    fprintf(stderr, "\n");
+    fprintf(stderr, "\tIf the input file(s) version is equals to the version option:\n\
+\t  No change in version (neither data creation nor data loss)\n\
+\tIf the input file(s) version is strictly less than the version option:\n\
+\t Data for version option are set to default values: 0, NaN, NULL\n\
+\tIf the input file(s) version is strictly greater than the version option:\n\
+\t  Data are those of the lower version.\n");
+    fprintf(stderr, "\n");
     psArgumentHelp(arguments);
+    fprintf(stderr, "\t\tCMF file version can be set to either 1 for PS1_DV1 or 2 for PS1_DV1\n");
+    fprintf(stderr, "\t\tSee IPP-MOPS ICD for details\n");
     psLibFinalize();
     exit(PS_EXIT_CONFIG_ERROR);
@@ -74,6 +92,5 @@
     psMetadataAddF32(arguments, PS_LIST_TAIL, "-zp_error", 0, "Error in magnitude zero point", NAN);
     psMetadataAddF32(arguments, PS_LIST_TAIL, "-astrom_rms", 0, "Astrometric solution RMS", NAN);
-    psMetadataAddU16(arguments, PS_LIST_TAIL, "-version", 0, "Parameters version (see ICD)", 0);
-
+    psMetadataAddU16(arguments, PS_LIST_TAIL, "-version", 0, "CMF file version", 0);
     if (argc == 1 || !psArgumentParse(arguments, &argc, argv) || argc != 3) {
         usage(argv[0], arguments);
Index: trunk/ppTranslate/src/ppMopsWrite.c
===================================================================
--- trunk/ppTranslate/src/ppMopsWrite.c	(revision 29565)
+++ trunk/ppTranslate/src/ppMopsWrite.c	(revision 29567)
@@ -52,5 +52,5 @@
     //New field in header that tells about the CMF version
     char cmfVersion[8];
-    sprintf(cmfVersion, "PS1_DV%d", args->version);
+    sprintf(cmfVersion, PS1_DV_FORMAT, args->version);
     psMetadataAddStr(header, PS_LIST_TAIL, "CMFVERSION", 0, "CMF version", cmfVersion);