Index: HDDefs.h
===================================================================
diff -u -rb78aa2b39798c5dedac4236d030fbb49112be04d -r7989a1f5f57a257944071fad12b52d5ba71d599b
--- HDDefs.h	(.../HDDefs.h)	(revision b78aa2b39798c5dedac4236d030fbb49112be04d)
+++ HDDefs.h	(.../HDDefs.h)	(revision 7989a1f5f57a257944071fad12b52d5ba71d599b)
@@ -7,8 +7,8 @@
 *
 * @file    HDDefs.h
 *
-* @author  (last)      Dara Navaei
-* @date    (last)      11-Jan-2023
+* @author  (last)      Michael Garthwaite
+* @date    (last)      19-Jan-2023
 *
 * @author  (original)  Sean Nash
 * @date    (original)  29-May-2020
@@ -747,6 +747,7 @@
     HD_EVENT_RSRVR_1_LOAD_CELL_END_VALUES,                              ///< HD reservoir 2 load cells end values
     HD_EVENT_RSRVR_2_LOAD_CELL_START_VALUES,                            ///< HD reservoir 2 load cells start values
     HD_EVENT_RSRVR_2_LOAD_CELL_END_VALUES,                              ///< HD reservoir 2 load cells end values
+    HD_EVENT_SUB_STATE_CHANGE,                                          ///< HD Op sub-state change event
     NUM_OF_EVENT_IDS                                                    ///< Total number of HD events
 };
 typedef enum HD_Event_List HD_EVENT_ID_T;                               ///< Type for HD event list enumeration