diff --git a/.vs/IoTGateway/DesignTimeBuild/.dtbcache.v2 b/.vs/IoTGateway/DesignTimeBuild/.dtbcache.v2
index 0c0f44d..2a9d283 100644
Binary files a/.vs/IoTGateway/DesignTimeBuild/.dtbcache.v2 and b/.vs/IoTGateway/DesignTimeBuild/.dtbcache.v2 differ
diff --git a/.vs/IoTGateway/v16/.suo b/.vs/IoTGateway/v16/.suo
index de2fcc3..6163207 100644
Binary files a/.vs/IoTGateway/v16/.suo and b/.vs/IoTGateway/v16/.suo differ
diff --git a/IoTGateway/IoTGateway.csproj b/IoTGateway/IoTGateway.csproj
index f9281df..e7baa97 100644
--- a/IoTGateway/IoTGateway.csproj
+++ b/IoTGateway/IoTGateway.csproj
@@ -20,6 +20,7 @@
     <PackageReference Include="MQTTnet.AspNetCore" Version="3.1.1" />
     <PackageReference Include="MQTTnet.Extensions.ManagedClient" Version="3.1.1" />
     <PackageReference Include="MQTTnet.Extensions.Rpc" Version="3.1.1" />
+    <PackageReference Include="System.IO.Ports" Version="6.0.0" />
 </ItemGroup>
 
   <ItemGroup>
diff --git a/Plugins/Drivers/DriverModbusMaster/DriverModbusMaster.csproj b/Plugins/Drivers/DriverModbusMaster/DriverModbusMaster.csproj
index 8579554..cec66fb 100644
--- a/Plugins/Drivers/DriverModbusMaster/DriverModbusMaster.csproj
+++ b/Plugins/Drivers/DriverModbusMaster/DriverModbusMaster.csproj
@@ -7,7 +7,11 @@
 	</PropertyGroup>
 
 	<ItemGroup>
-		<ProjectReference Include="..\..\PluginInterface\PluginInterface.csproj" />
+	  <PackageReference Include="System.IO.Ports" Version="6.0.0" />
+	</ItemGroup>
+
+	<ItemGroup>
+	  <ProjectReference Include="..\..\PluginInterface\PluginInterface.csproj" />
 	</ItemGroup>
 
 	<ItemGroup>
diff --git a/Plugins/Drivers/DriverModbusMaster/ModbusMaster.cs b/Plugins/Drivers/DriverModbusMaster/ModbusMaster.cs
index fb1b49d..440ae77 100644
--- a/Plugins/Drivers/DriverModbusMaster/ModbusMaster.cs
+++ b/Plugins/Drivers/DriverModbusMaster/ModbusMaster.cs
@@ -74,7 +74,22 @@ namespace DriverModbusMaster
         {
             get
             {
-                return clientTcp != null && master != null && clientTcp.Connected;
+                switch (Master_TYPE)
+                {
+                    case Master_TYPE.Tcp:
+                    case Master_TYPE.RtuOnTcp:
+                    case Master_TYPE.AsciiOnTcp:
+                        return clientTcp != null && master != null && clientTcp.Connected;
+                    case Master_TYPE.Udp:
+                    case Master_TYPE.RtuOnUdp:
+                    case Master_TYPE.AsciiOnUdp:
+                        return clientUdp != null && master != null && clientUdp.Client.Connected ;
+                    case Master_TYPE.Rtu:
+                    case Master_TYPE.Ascii:
+                        return port != null && master != null && port.IsOpen;
+                    default:
+                        return false;
+                }
             }
         }
 
@@ -124,7 +139,7 @@ namespace DriverModbusMaster
                         break;
                 }
             }
-            catch (Exception)
+            catch (Exception ex)
             {
                 return false;
             }
@@ -225,7 +240,7 @@ namespace DriverModbusMaster
         private DriverReturnValueModel ReadRegistersBuffers(byte FunCode, DriverAddressIoArgModel ioarg)
         {
             DriverReturnValueModel ret = new() { StatusType = VaribaleStatusTypeEnum.Good };
-            if (!clientTcp.Connected)
+            if (!IsConnected)
                 ret.StatusType = VaribaleStatusTypeEnum.Bad;
             else
             {
diff --git a/Plugins/Drivers/DriverModbusMaster/System.IO.Ports.dll b/Plugins/Drivers/DriverModbusMaster/System.IO.Ports.dll
deleted file mode 100644
index bd5d3fb..0000000
Binary files a/Plugins/Drivers/DriverModbusMaster/System.IO.Ports.dll and /dev/null differ