diff --git a/rec-nan.patch b/rec-nan.patch
new file mode 100644
index 000000000..f61070fcc
--- /dev/null
+++ b/rec-nan.patch
@@ -0,0 +1,190 @@
+=== modified file 'src/rec/aiRecord.c'
+--- src/rec/aiRecord.c	2010-10-05 19:27:37 +0000
++++ src/rec/aiRecord.c	2012-10-07 02:48:01 +0000
+@@ -385,7 +385,7 @@
+ 	/* check for value change */
+ 	delta = prec->mlst - prec->val;
+ 	if(delta<0.0) delta = -delta;
+-	if (delta > prec->mdel) {
++	if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
+ 		/* post events for value change */
+ 		monitor_mask |= DBE_VALUE;
+ 		/* update last value monitored */
+@@ -395,7 +395,7 @@
+ 	/* check for archive change */
+ 	delta = prec->alst - prec->val;
+ 	if(delta<0.0) delta = -delta;
+-	if (delta > prec->adel) {
++	if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
+ 		/* post events on value field for archive change */
+ 		monitor_mask |= DBE_LOG;
+ 		/* update last archive value monitored */
+
+=== modified file 'src/rec/aoRecord.c'
+--- src/rec/aoRecord.c	2010-10-05 19:27:37 +0000
++++ src/rec/aoRecord.c	2012-10-07 02:48:01 +0000
+@@ -484,7 +484,7 @@
+         /* check for value change */
+         delta = prec->mlst - prec->val;
+         if(delta<0.0) delta = -delta;
+-        if (delta > prec->mdel) {
++        if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
+                 /* post events for value change */
+                 monitor_mask |= DBE_VALUE;
+                 /* update last value monitored */
+@@ -493,7 +493,7 @@
+         /* check for archive change */
+         delta = prec->alst - prec->val;
+         if(delta<0.0) delta = -delta;
+-        if (delta > prec->adel) {
++        if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
+                 /* post events on value field for archive change */
+                 monitor_mask |= DBE_LOG;
+                 /* update last archive value monitored */
+
+=== modified file 'src/rec/calcRecord.c'
+--- src/rec/calcRecord.c	2010-11-24 19:35:04 +0000
++++ src/rec/calcRecord.c	2012-10-07 02:48:01 +0000
+@@ -310,7 +310,7 @@
+     /* check for value change */
+     delta = prec->mlst - prec->val;
+     if (delta < 0.0) delta = -delta;
+-    if (delta > prec->mdel) {
++    if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
+ 	/* post events for value change */
+ 	monitor_mask |= DBE_VALUE;
+ 	/* update last value monitored */
+@@ -319,7 +319,7 @@
+     /* check for archive change */
+     delta = prec->alst - prec->val;
+     if (delta < 0.0) delta = -delta;
+-    if (delta > prec->adel) {
++    if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
+ 	/* post events on value field for archive change */
+ 	monitor_mask |= DBE_LOG;
+ 	/* update last archive value monitored */
+
+=== modified file 'src/rec/calcoutRecord.c'
+--- src/rec/calcoutRecord.c	2012-03-08 15:47:38 +0000
++++ src/rec/calcoutRecord.c	2012-10-07 02:48:01 +0000
+@@ -209,7 +209,7 @@
+ static long process(calcoutRecord *prec)
+ {
+     rpvtStruct *prpvt = prec->rpvt;
+-    int doOutput = 0;
++    int doOutput;
+ 
+     if (!prec->pact) {
+         prec->pact = TRUE;
+@@ -231,21 +231,22 @@
+             doOutput = 1;
+             break;
+         case calcoutOOPT_On_Change:
+-            if (fabs(prec->pval - prec->val) > prec->mdel) doOutput = 1;
++            doOutput = ! (fabs(prec->pval - prec->val) <= prec->mdel);
+             break;
+         case calcoutOOPT_Transition_To_Zero:
+-            if ((prec->pval != 0.0) && (prec->val == 0.0)) doOutput = 1;
++            doOutput = ((prec->pval != 0.0) && (prec->val == 0.0));
+             break;
+         case calcoutOOPT_Transition_To_Non_zero:
+-            if ((prec->pval == 0.0) && (prec->val != 0.0)) doOutput = 1;
++            doOutput = ((prec->pval == 0.0) && (prec->val != 0.0));
+             break;
+         case calcoutOOPT_When_Zero:
+-            if (prec->val == 0.0) doOutput = 1;
++            doOutput = (prec->val == 0.0);
+             break;
+         case calcoutOOPT_When_Non_zero:
+-            if (prec->val != 0.0) doOutput = 1;
++            doOutput = (prec->val != 0.0);
+             break;
+         default:
++	    doOutput = 0;
+             break;
+         }
+         prec->pval = prec->val;
+@@ -584,7 +585,7 @@
+         /* check for value change */
+         delta = prec->mlst - prec->val;
+         if (delta<0.0) delta = -delta;
+-        if (delta > prec->mdel) {
++        if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
+                 /* post events for value change */
+                 monitor_mask |= DBE_VALUE;
+                 /* update last value monitored */
+@@ -593,7 +594,7 @@
+         /* check for archive change */
+         delta = prec->alst - prec->val;
+         if (delta<0.0) delta = -delta;
+-        if (delta > prec->adel) {
++        if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
+                 /* post events on value field for archive change */
+                 monitor_mask |= DBE_LOG;
+                 /* update last archive value monitored */
+
+=== modified file 'src/rec/dfanoutRecord.c'
+--- src/rec/dfanoutRecord.c	2010-10-05 19:27:37 +0000
++++ src/rec/dfanoutRecord.c	2012-10-07 02:48:01 +0000
+@@ -267,7 +267,7 @@
+         /* check for value change */
+         delta = prec->mlst - prec->val;
+         if(delta<0) delta = -delta;
+-        if (delta > prec->mdel) {
++        if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
+                 /* post events for value change */
+                 monitor_mask |= DBE_VALUE;
+                 /* update last value monitored */
+@@ -276,7 +276,7 @@
+         /* check for archive change */
+         delta = prec->alst - prec->val;
+         if(delta<0) delta = -delta;
+-        if (delta > prec->adel) {
++        if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
+                 /* post events on value field for archive change */
+                 monitor_mask |= DBE_LOG;
+                 /* update last archive value monitored */
+
+=== modified file 'src/rec/selRecord.c'
+--- src/rec/selRecord.c	2010-10-05 19:27:37 +0000
++++ src/rec/selRecord.c	2012-10-07 02:48:01 +0000
+@@ -300,7 +300,7 @@
+     /* check for value change */
+     delta = prec->mlst - prec->val;
+     if(delta<0.0) delta = -delta;
+-    if (delta > prec->mdel) {
++    if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
+         /* post events for value change */
+         monitor_mask |= DBE_VALUE;
+         /* update last value monitored */
+@@ -309,7 +309,7 @@
+     /* check for archive change */
+     delta = prec->alst - prec->val;
+     if(delta<0.0) delta = -delta;
+-    if (delta > prec->adel) {
++    if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
+         /* post events on value field for archive change */
+         monitor_mask |= DBE_LOG;
+         /* update last archive value monitored */
+
+=== modified file 'src/rec/subRecord.c'
+--- src/rec/subRecord.c	2010-10-05 19:27:37 +0000
++++ src/rec/subRecord.c	2012-10-07 02:48:01 +0000
+@@ -353,7 +353,7 @@
+     /* check for value change */
+     delta = prec->val - prec->mlst;
+     if (delta < 0.0) delta = -delta;
+-    if (delta > prec->mdel) {
++    if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
+         /* post events for value change */
+         monitor_mask |= DBE_VALUE;
+         /* update last value monitored */
+@@ -362,7 +362,7 @@
+     /* check for archive change */
+     delta = prec->val - prec->alst;
+     if (delta < 0.0) delta = -delta;
+-    if (delta > prec->adel) {
++    if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
+         /* post events on value field for archive change */
+         monitor_mask |= DBE_LOG;
+         /* update last archive value monitored */
diff --git a/src/rec/aiRecord.c b/src/rec/aiRecord.c
index 657df122b..07111ab0d 100644
--- a/src/rec/aiRecord.c
+++ b/src/rec/aiRecord.c
@@ -385,7 +385,7 @@ static void monitor(aiRecord *prec)
 	/* check for value change */
 	delta = prec->mlst - prec->val;
 	if(delta<0.0) delta = -delta;
-	if (delta > prec->mdel) {
+	if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
 		/* post events for value change */
 		monitor_mask |= DBE_VALUE;
 		/* update last value monitored */
@@ -395,7 +395,7 @@ static void monitor(aiRecord *prec)
 	/* check for archive change */
 	delta = prec->alst - prec->val;
 	if(delta<0.0) delta = -delta;
-	if (delta > prec->adel) {
+	if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
 		/* post events on value field for archive change */
 		monitor_mask |= DBE_LOG;
 		/* update last archive value monitored */
diff --git a/src/rec/aoRecord.c b/src/rec/aoRecord.c
index d166c22ac..2f2e6c968 100644
--- a/src/rec/aoRecord.c
+++ b/src/rec/aoRecord.c
@@ -484,7 +484,7 @@ static void monitor(aoRecord *prec)
         /* check for value change */
         delta = prec->mlst - prec->val;
         if(delta<0.0) delta = -delta;
-        if (delta > prec->mdel) {
+        if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
                 /* post events for value change */
                 monitor_mask |= DBE_VALUE;
                 /* update last value monitored */
@@ -493,7 +493,7 @@ static void monitor(aoRecord *prec)
         /* check for archive change */
         delta = prec->alst - prec->val;
         if(delta<0.0) delta = -delta;
-        if (delta > prec->adel) {
+        if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
                 /* post events on value field for archive change */
                 monitor_mask |= DBE_LOG;
                 /* update last archive value monitored */
diff --git a/src/rec/calcRecord.c b/src/rec/calcRecord.c
index 6af2448e7..e202b4276 100644
--- a/src/rec/calcRecord.c
+++ b/src/rec/calcRecord.c
@@ -310,7 +310,7 @@ static void monitor(calcRecord *prec)
     /* check for value change */
     delta = prec->mlst - prec->val;
     if (delta < 0.0) delta = -delta;
-    if (delta > prec->mdel) {
+    if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
 	/* post events for value change */
 	monitor_mask |= DBE_VALUE;
 	/* update last value monitored */
@@ -319,7 +319,7 @@ static void monitor(calcRecord *prec)
     /* check for archive change */
     delta = prec->alst - prec->val;
     if (delta < 0.0) delta = -delta;
-    if (delta > prec->adel) {
+    if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
 	/* post events on value field for archive change */
 	monitor_mask |= DBE_LOG;
 	/* update last archive value monitored */
diff --git a/src/rec/calcoutRecord.c b/src/rec/calcoutRecord.c
index 95b7c0d10..0700947f8 100644
--- a/src/rec/calcoutRecord.c
+++ b/src/rec/calcoutRecord.c
@@ -211,7 +211,7 @@ static long init_record(calcoutRecord *prec, int pass)
 static long process(calcoutRecord *prec)
 {
     rpvtStruct *prpvt = prec->rpvt;
-    int doOutput = 0;
+    int doOutput;
 
     if (!prec->pact) {
         prec->pact = TRUE;
@@ -233,21 +233,22 @@ static long process(calcoutRecord *prec)
             doOutput = 1;
             break;
         case calcoutOOPT_On_Change:
-            if (fabs(prec->pval - prec->val) > prec->mdel) doOutput = 1;
+            doOutput = ! (fabs(prec->pval - prec->val) <= prec->mdel);
             break;
         case calcoutOOPT_Transition_To_Zero:
-            if ((prec->pval != 0.0) && (prec->val == 0.0)) doOutput = 1;
+            doOutput = ((prec->pval != 0.0) && (prec->val == 0.0));
             break;
         case calcoutOOPT_Transition_To_Non_zero:
-            if ((prec->pval == 0.0) && (prec->val != 0.0)) doOutput = 1;
+            doOutput = ((prec->pval == 0.0) && (prec->val != 0.0));
             break;
         case calcoutOOPT_When_Zero:
-            if (prec->val == 0.0) doOutput = 1;
+            doOutput = (prec->val == 0.0);
             break;
         case calcoutOOPT_When_Non_zero:
-            if (prec->val != 0.0) doOutput = 1;
+            doOutput = (prec->val != 0.0);
             break;
         default:
+	    doOutput = 0;
             break;
         }
         prec->pval = prec->val;
@@ -580,7 +581,7 @@ static void monitor(calcoutRecord *prec)
         /* check for value change */
         delta = prec->mlst - prec->val;
         if (delta<0.0) delta = -delta;
-        if (delta > prec->mdel) {
+        if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
                 /* post events for value change */
                 monitor_mask |= DBE_VALUE;
                 /* update last value monitored */
@@ -589,7 +590,7 @@ static void monitor(calcoutRecord *prec)
         /* check for archive change */
         delta = prec->alst - prec->val;
         if (delta<0.0) delta = -delta;
-        if (delta > prec->adel) {
+        if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
                 /* post events on value field for archive change */
                 monitor_mask |= DBE_LOG;
                 /* update last archive value monitored */
diff --git a/src/rec/dfanoutRecord.c b/src/rec/dfanoutRecord.c
index ba6c579aa..e2efc931c 100644
--- a/src/rec/dfanoutRecord.c
+++ b/src/rec/dfanoutRecord.c
@@ -267,7 +267,7 @@ static void monitor(dfanoutRecord *prec)
         /* check for value change */
         delta = prec->mlst - prec->val;
         if(delta<0) delta = -delta;
-        if (delta > prec->mdel) {
+        if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
                 /* post events for value change */
                 monitor_mask |= DBE_VALUE;
                 /* update last value monitored */
@@ -276,7 +276,7 @@ static void monitor(dfanoutRecord *prec)
         /* check for archive change */
         delta = prec->alst - prec->val;
         if(delta<0) delta = -delta;
-        if (delta > prec->adel) {
+        if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
                 /* post events on value field for archive change */
                 monitor_mask |= DBE_LOG;
                 /* update last archive value monitored */
diff --git a/src/rec/selRecord.c b/src/rec/selRecord.c
index 919438962..542b2163b 100644
--- a/src/rec/selRecord.c
+++ b/src/rec/selRecord.c
@@ -300,7 +300,7 @@ static void monitor(selRecord *prec)
     /* check for value change */
     delta = prec->mlst - prec->val;
     if(delta<0.0) delta = -delta;
-    if (delta > prec->mdel) {
+    if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
         /* post events for value change */
         monitor_mask |= DBE_VALUE;
         /* update last value monitored */
@@ -309,7 +309,7 @@ static void monitor(selRecord *prec)
     /* check for archive change */
     delta = prec->alst - prec->val;
     if(delta<0.0) delta = -delta;
-    if (delta > prec->adel) {
+    if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
         /* post events on value field for archive change */
         monitor_mask |= DBE_LOG;
         /* update last archive value monitored */
diff --git a/src/rec/subRecord.c b/src/rec/subRecord.c
index eb92e137b..1cf2d4868 100644
--- a/src/rec/subRecord.c
+++ b/src/rec/subRecord.c
@@ -353,7 +353,7 @@ static void monitor(subRecord *prec)
     /* check for value change */
     delta = prec->val - prec->mlst;
     if (delta < 0.0) delta = -delta;
-    if (delta > prec->mdel) {
+    if (!(delta <= prec->mdel)) { /* Handles MDEL == NAN */
         /* post events for value change */
         monitor_mask |= DBE_VALUE;
         /* update last value monitored */
@@ -362,7 +362,7 @@ static void monitor(subRecord *prec)
     /* check for archive change */
     delta = prec->val - prec->alst;
     if (delta < 0.0) delta = -delta;
-    if (delta > prec->adel) {
+    if (!(delta <= prec->adel)) { /* Handles ADEL == NAN */
         /* post events on value field for archive change */
         monitor_mask |= DBE_LOG;
         /* update last archive value monitored */