public static byte[] ProcessSlaveFunction(ModbusTCPFrame frame)
{
DataModel dataModel;
if (ModbusTCP.Slaves.Any(s => s.Key == frame.UnitIdentifier))
{
dataModel = ModbusTCP.Slaves.FirstOrDefault(s => s.Key == frame.UnitIdentifier).Value;
}
else
{
dataModel = DataModel.Create(frame.UnitIdentifier);
ModbusTCP.Slaves.Add(frame.UnitIdentifier, dataModel);
}
switch (frame.FunctionCode)
{
case FunctionCode.ReadCoils:
return(dataModel.ReadCoils(frame.Data));
case FunctionCode.ReadDiscreteInputs:
return(dataModel.ReadDiscreteInputs(frame.Data));
case FunctionCode.WriteSingleCoil:
return(dataModel.WriteSingleCoil(frame.Data));
case FunctionCode.WriteMultipleCoils:
return(dataModel.WriteMultipleCoils(frame.Data));
}
return(new byte[0]);
}
public void Start()
{
try
{
_server.Start();
// Buffer for reading data
var bytes = new byte[1024];
string data = null;
while (true)
{
Console.Write("Waiting for a connection... ");
var client = _server.AcceptTcpClient();
Console.WriteLine("Connected!");
// Get a stream object for reading and writing
var stream = client.GetStream();
// Loop to receive all the data sent by the client.
while ((stream.Read(bytes, 0, bytes.Length)) != 0)
{
//Console.WriteLine("Received: {0}", Formatter.ByteArrayToString(bytes));
var frame = new ModbusTCPFrame(bytes);
#if DEBUG
Console.WriteLine("Transaction identifier: {0}", frame.TransactionIdentifier);
Console.WriteLine("Protocol identifier: {0}", frame.ProtocolIdentifier);
Console.WriteLine("Length field: {0}", frame.LengthField);
Console.WriteLine("Unit identifier: {0}", frame.UnitIdentifier);
Console.WriteLine("Function code: {0}", frame.FunctionCode.GetDescription());
Console.WriteLine("Data: {0}", Formatter.ByteArrayToString(frame.Data));
#endif
byte[] returnData = FunctionMapping.ProcessSlaveFunction(frame);
byte transActIdb0 = (byte)frame.TransactionIdentifier,
transActIdb1 = (byte)(frame.TransactionIdentifier >> 8);
byte unitId = (byte)frame.UnitIdentifier;
byte function = (byte)frame.FunctionCode;
byte dataLenth = (byte)(returnData.Length + 2);
byte[] header = new byte[] { transActIdb1, transActIdb0, 0x00, 0x00, 0x00, dataLenth, unitId, function };
byte[] msg = _combine(header, returnData);
// Send back a response.
stream.Write(msg, 0, msg.Length);
#if DEBUG
Console.WriteLine("Sent: {0}", Formatter.ByteArrayToString(msg));
#endif
}
// Shutdown and end connection
client.Close();
}
}
catch (Exception e)
{
Console.WriteLine(e);
}
finally
{
// Stop listening for new clients.
_server.Stop();
}
}
