diff --git a/src/cas/example/simple/exVectorPV.cc b/src/cas/example/simple/exVectorPV.cc
index aa2ab7618..d855635a6 100644
--- a/src/cas/example/simple/exVectorPV.cc
+++ b/src/cas/example/simple/exVectorPV.cc
@@ -73,6 +73,12 @@ void exVectorPV::scan()
 		pDD->unreference();
 	}
 
+	//
+	// install the buffer into the DD
+	// (do this before we increment pF)
+	//
+	*pDD = pF;
+
 	//
 	// double check for reasonable bounds on the
 	// current value
@@ -104,11 +110,6 @@ void exVectorPV::scan()
 		*(pF++) = newValue;
 	}
 
-	//
-	// install the buffer into the DD
-	//
-	*pDD = pF;
-
         status = this->update (*pDD);
         if (status) {
                 errMessage (status, "scan update failed\n");