diff --git a/bacnet-stack/include/bacenum.h b/bacnet-stack/include/bacenum.h
index 2ab38db7..d3c37645 100644
--- a/bacnet-stack/include/bacenum.h
+++ b/bacnet-stack/include/bacenum.h
@@ -635,11 +635,12 @@ typedef enum {
     UNITS_REVOLUTIONS_PER_MINUTE = 104,
     UNITS_SQUARE_METERS_PER_NEWTON = 185,
     UNITS_WATTS_PER_METER_PER_DEGREE_KELVIN = 189,
-    UNITS_WATTS_PER_SQUARE_METER_DEGREE_KELVIN = 141
+    UNITS_WATTS_PER_SQUARE_METER_DEGREE_KELVIN = 141,
         /* Enumerated values 0-255 are reserved for definition by ASHRAE. */
         /* Enumerated values 256-65535 may be used by others subject to */
         /* the procedures and constraints described in Clause 23. */
         /* The last enumeration used in this version is 189. */
+    MAX_UNITS = 190
 } BACNET_ENGINEERING_UNITS;
 
 typedef enum {