diff --git a/HighWayIot.Plc/HighWayIot.Plc.csproj b/HighWayIot.Plc/HighWayIot.Plc.csproj
index dd306dc..1fac2c2 100644
--- a/HighWayIot.Plc/HighWayIot.Plc.csproj
+++ b/HighWayIot.Plc/HighWayIot.Plc.csproj
@@ -32,6 +32,10 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="HslCommunication, Version=12.1.3.0, Culture=neutral, PublicKeyToken=3d72ad3b6b5ec0e3, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
+      <HintPath>..\HighWayIot.Library\HslCommunication.dll</HintPath>
+    </Reference>
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.Xml.Linq" />