diff --git a/S7.Net/PLC.cs b/S7.Net/PLC.cs
index 35d038e..3ba4961 100644
--- a/S7.Net/PLC.cs
+++ b/S7.Net/PLC.cs
@@ -194,6 +194,7 @@ public void Close()
                 if (tcpClient.Connected) tcpClient.Close();
                 tcpClient = null; // Can not reuse TcpClient once connection gets closed.
             }
+            _stream = null;
         }
 
         private void AssertPduSizeForRead(ICollection<DataItem> dataItems)