diff --git a/Modbus.Net/ModBus.Net/BaseMachine.cs b/Modbus.Net/ModBus.Net/BaseMachine.cs
index 0e099f5..dc56831 100644
--- a/Modbus.Net/ModBus.Net/BaseMachine.cs
+++ b/Modbus.Net/ModBus.Net/BaseMachine.cs
@@ -76,6 +76,7 @@ namespace ModBus.Net
             {
                 BaseUtility.Disconnect();
             }
+            if (ans.Count == 0) ans = null;
             return ans;
         }