diff --git a/DvDt.cs b/DvDt.cs
index 886d8cd..5264635 100644
--- a/DvDt.cs
+++ b/DvDt.cs
@@ -29,7 +29,7 @@ namespace ln.types
         {
             DateTime now = DateTime.Now;
             double interval = (now - lastTimestamp).TotalSeconds;
-            if (interval != 0.0)
+            if (Math.Abs(interval) > double.Epsilon)
             {
                 double dV = value - lastValue;
                 Current = dV / interval;