diff --git a/Modbus.Net/Modbus.Net.Siemens/SiemensMachine.cs b/Modbus.Net/Modbus.Net.Siemens/SiemensMachine.cs
index 92c3697..06d3f29 100644
--- a/Modbus.Net/Modbus.Net.Siemens/SiemensMachine.cs
+++ b/Modbus.Net/Modbus.Net.Siemens/SiemensMachine.cs
@@ -12,6 +12,7 @@ namespace Modbus.Net.Siemens
         /// <summary>
         ///     构造函数
         /// </summary>
+        /// <param name="id">设备id号</param>
         /// <param name="connectionType">连接类型</param>
         /// <param name="connectionString">连接地址</param>
         /// <param name="model">设备类型</param>
@@ -19,11 +20,13 @@ namespace Modbus.Net.Siemens
         /// <param name="keepConnect">是否保持连接</param>
         /// <param name="slaveAddress">从站号</param>
         /// <param name="masterAddress">主站号</param>
+        /// <param name="src">本机模块位，0到7，仅200使用，其它型号不要填写</param>
+        /// <param name="dst">PLC模块位，0到7，仅200使用，其它型号不要填写</param>
         public SiemensMachine(TKey id, SiemensType connectionType, string connectionString, SiemensMachineModel model,
-            IEnumerable<AddressUnit<TUnitKey>> getAddresses, bool keepConnect, byte slaveAddress, byte masterAddress)
+            IEnumerable<AddressUnit<TUnitKey>> getAddresses, bool keepConnect, byte slaveAddress, byte masterAddress, byte src = 1, byte dst = 0)
             : base(id, getAddresses, keepConnect, slaveAddress, masterAddress)
         {
-            BaseUtility = new SiemensUtility(connectionType, connectionString, model, slaveAddress, masterAddress);
+            BaseUtility = new SiemensUtility(connectionType, connectionString, model, slaveAddress, masterAddress, src, dst);
             AddressFormater = new AddressFormaterSiemens();
             AddressCombiner = new AddressCombinerContinus<TUnitKey>(AddressTranslator, 100);
             AddressCombinerSet = new AddressCombinerContinus<TUnitKey>(AddressTranslator, 100);
@@ -32,15 +35,18 @@ namespace Modbus.Net.Siemens
         /// <summary>
         ///     构造函数
         /// </summary>
+        /// <param name="id">设备id号</param>
         /// <param name="connectionType">连接类型</param>
         /// <param name="connectionString">连接地址</param>
         /// <param name="model">设备类型</param>
         /// <param name="getAddresses">读写的地址</param>
         /// <param name="slaveAddress">从站号</param>
         /// <param name="masterAddress">主站号</param>
+        /// <param name="src">本机模块位，0到7，仅200使用，其它型号不要填写</param>
+        /// <param name="dst">PLC模块位，0到7，仅200使用，其它型号不要填写</param>
         public SiemensMachine(TKey id, SiemensType connectionType, string connectionString, SiemensMachineModel model,
-            IEnumerable<AddressUnit<TUnitKey>> getAddresses, byte slaveAddress, byte masterAddress)
-            : this(id, connectionType, connectionString, model, getAddresses, false, slaveAddress, masterAddress)
+            IEnumerable<AddressUnit<TUnitKey>> getAddresses, byte slaveAddress, byte masterAddress, byte src = 1, byte dst = 0)
+            : this(id, connectionType, connectionString, model, getAddresses, false, slaveAddress, masterAddress, src, dst)
         {
         }
     }
@@ -53,6 +59,7 @@ namespace Modbus.Net.Siemens
         /// <summary>
         ///     构造函数
         /// </summary>
+        /// <param name="id">设备id号</param>
         /// <param name="connectionType">连接类型</param>
         /// <param name="connectionString">连接地址</param>
         /// <param name="model">设备类型</param>
@@ -60,11 +67,13 @@ namespace Modbus.Net.Siemens
         /// <param name="keepConnect">是否保持连接</param>
         /// <param name="slaveAddress">从站号</param>
         /// <param name="masterAddress">主站号</param>
+        /// <param name="src">本机模块位，0到7，仅200使用，其它型号不要填写</param>
+        /// <param name="dst">PLC模块位，0到7，仅200使用，其它型号不要填写</param>
         public SiemensMachine(string id, SiemensType connectionType, string connectionString, SiemensMachineModel model,
-            IEnumerable<AddressUnit> getAddresses, bool keepConnect, byte slaveAddress, byte masterAddress)
+            IEnumerable<AddressUnit> getAddresses, bool keepConnect, byte slaveAddress, byte masterAddress, byte src = 1, byte dst = 0)
             : base(id, getAddresses, keepConnect, slaveAddress, masterAddress)
         {
-            BaseUtility = new SiemensUtility(connectionType, connectionString, model, slaveAddress, masterAddress);
+            BaseUtility = new SiemensUtility(connectionType, connectionString, model, slaveAddress, masterAddress, src, dst);
             AddressFormater = new AddressFormaterSiemens();
             AddressCombiner = new AddressCombinerContinus(AddressTranslator, 100);
             AddressCombinerSet = new AddressCombinerContinus(AddressTranslator, 100);
@@ -73,15 +82,18 @@ namespace Modbus.Net.Siemens
         /// <summary>
         ///     构造函数
         /// </summary>
+        /// <param name="id">设备id号</param>
         /// <param name="connectionType">连接类型</param>
         /// <param name="connectionString">连接地址</param>
         /// <param name="model">设备类型</param>
         /// <param name="getAddresses">读写的地址</param>
         /// <param name="slaveAddress">从站号</param>
         /// <param name="masterAddress">主站号</param>
+        /// <param name="src">本机模块位，0到7，仅200使用，其它型号不要填写</param>
+        /// <param name="dst">PLC模块位，0到7，仅200使用，其它型号不要填写</param>
         public SiemensMachine(string id, SiemensType connectionType, string connectionString, SiemensMachineModel model,
-            IEnumerable<AddressUnit> getAddresses, byte slaveAddress, byte masterAddress)
-            : this(id, connectionType, connectionString, model, getAddresses, false, slaveAddress, masterAddress)
+            IEnumerable<AddressUnit> getAddresses, byte slaveAddress, byte masterAddress, byte src = 1, byte dst = 0)
+            : this(id, connectionType, connectionString, model, getAddresses, false, slaveAddress, masterAddress, src, dst)
         {
         }
     }
diff --git a/Modbus.Net/Modbus.Net.Siemens/SiemensUtility.cs b/Modbus.Net/Modbus.Net.Siemens/SiemensUtility.cs
index b3762fa..b6a75a4 100644
--- a/Modbus.Net/Modbus.Net.Siemens/SiemensUtility.cs
+++ b/Modbus.Net/Modbus.Net.Siemens/SiemensUtility.cs
@@ -66,6 +66,8 @@ namespace Modbus.Net.Siemens
         private readonly byte _tdpuSize;
         private readonly ushort _tsapDst;
 
+        private ushort _sendCount;
+
         private SiemensType _siemensType;
 
         /// <summary>
@@ -76,8 +78,10 @@ namespace Modbus.Net.Siemens
         /// <param name="model">设备类型</param>
         /// <param name="slaveAddress">从站地址</param>
         /// <param name="masterAddress">主站地址</param>
+        /// <param name="src">本机模块位，0到7，仅200使用，其它型号不要填写</param>
+        /// <param name="dst">PLC模块位，0到7，仅200使用，其它型号不要填写</param>
         public SiemensUtility(SiemensType connectionType, string connectionString, SiemensMachineModel model,
-            byte slaveAddress, byte masterAddress) : base(slaveAddress, masterAddress)
+            byte slaveAddress, byte masterAddress, byte src = 1, byte dst = 0) : base(slaveAddress, masterAddress)
         {
             ConnectionString = connectionString;
             switch (model)
@@ -85,8 +89,8 @@ namespace Modbus.Net.Siemens
                 case SiemensMachineModel.S7_200:
                 {
                     _tdpuSize = 0x09;
-                    _taspSrc = 0x1001;
-                    _tsapDst = 0x1000;
+                    _taspSrc = (ushort)(0x1000 + src);
+                    _tsapDst = (ushort)(0x1000 + dst);
                     _maxCalling = 0x0001;
                     _maxCalled = 0x0001;
                     _maxPdu = 0x03c0;
@@ -131,6 +135,7 @@ namespace Modbus.Net.Siemens
             }
             ConnectionType = connectionType;
             AddressTranslator = new AddressTranslatorSiemens();
+            _sendCount = 0;
         }
 
         /// <summary>
@@ -231,8 +236,9 @@ namespace Modbus.Net.Siemens
         {
             try
             {
+                _sendCount = (ushort)(_sendCount % 65535 + 1);
                 var readRequestSiemensInputStruct = new ReadRequestSiemensInputStruct(SlaveAddress, MasterAddress,
-                    0xd3c7, SiemensTypeCode.Byte, startAddress, (ushort) getByteCount, AddressTranslator);
+                    _sendCount, SiemensTypeCode.Byte, startAddress, (ushort) getByteCount, AddressTranslator);
                 var readRequestSiemensOutputStruct =
                     await
                         Wrapper.SendReceiveAsync<ReadRequestSiemensOutputStruct>(
@@ -257,8 +263,9 @@ namespace Modbus.Net.Siemens
         {
             try
             {
+                _sendCount = (ushort)(_sendCount % 65535 + 1);
                 var writeRequestSiemensInputStruct = new WriteRequestSiemensInputStruct(SlaveAddress, MasterAddress,
-                    0xd3c8, startAddress, setContents, AddressTranslator);
+                    _sendCount, startAddress, setContents, AddressTranslator);
                 var writeRequestSiemensOutputStruct =
                     await
                         Wrapper.SendReceiveAsync<WriteRequestSiemensOutputStruct>(