diff --git a/src/rec/longinRecord.c b/src/rec/longinRecord.c
index a7b493e53..c839ad292 100644
--- a/src/rec/longinRecord.c
+++ b/src/rec/longinRecord.c
@@ -298,7 +298,8 @@ static void monitor(plongin)
 	/* check for value change */
 	delta = plongin->mlst - plongin->val;
 	if(delta<0) delta = -delta;
-	if (delta > plongin->mdel) {
+        /*If delta=0x80000000 then delta==-delta*/
+        if (delta > plongin->mdel || delta==0x80000000) {
 		/* post events for value change */
 		monitor_mask |= DBE_VALUE;
 		/* update last value monitored */
diff --git a/src/rec/longoutRecord.c b/src/rec/longoutRecord.c
index e95c3c5c5..5156dd469 100644
--- a/src/rec/longoutRecord.c
+++ b/src/rec/longoutRecord.c
@@ -339,7 +339,8 @@ static void monitor(plongout)
         /* check for value change */
         delta = plongout->mlst - plongout->val;
         if(delta<0) delta = -delta;
-        if (delta > plongout->mdel) {
+        /*If delta=0x80000000 then delta==-delta*/
+        if (delta > plongout->mdel || delta==0x80000000) {
                 /* post events for value change */
                 monitor_mask |= DBE_VALUE;
                 /* update last value monitored */