//TODO: Evaluate ReadHoldingRegisters return type. Should this be words? Bytes? something else?
// At the core of the protocol, this is really returning words. The words can be interpreted
// as floating point, integers, unsigned, etc.
public IEnumerable <Int16> ReadHoldingRegisters(Int16 startRegister, Int16 count)
{
List <byte> mbPacket = new List <byte>();
mbPacket.Add(0x03);
mbPacket.AddRange(startRegister.GetBytes());
mbPacket.AddRange(count.GetBytes());
MBAP mbap = MBAP.Create((Int16)(mbPacket.Count + 1), 0);
mbPacket.InsertRange(0, mbap.GetBytes());
tcpClient.GetStream().Write(mbPacket.ToArray(), 0, mbPacket.Count);
byte[] readBuffer = new byte[500];
tcpClient.GetStream().Read(readBuffer, 0, 500);
int returnCount = (int)readBuffer[8];
List <Int16> returnList = new List <short>();
for (int i = 9; i < 9 + returnCount; i += 2)
{
returnList.Add(Int16Extensions.FromBytes(readBuffer[i], readBuffer[i + 1]));
}
return(returnList);
}
public void WriteMultipleRegisters(Int16 startRegister, IEnumerable <Int16> values)
{
List <byte> mbPacket = new List <byte>();
mbPacket.Add(0x10);
mbPacket.AddRange(startRegister.GetBytes());
mbPacket.AddRange(((Int16)(values.Count())).GetBytes());
var data = values.SelectMany(v => new List <byte>()
{
v.HighByte(), v.LowByte()
});
mbPacket.Add(((Int16)data.Count()).LowByte());
mbPacket.AddRange(data.ToArray());
MBAP mbap = MBAP.Create((Int16)(mbPacket.Count + 1), 0);
mbPacket.InsertRange(0, mbap.GetBytes());
tcpClient.GetStream().Write(mbPacket.ToArray(), 0, mbPacket.Count);
byte[] buffer = new byte[500];
//technically, the operation should be confirmed by examining the response
tcpClient.GetStream().Read(buffer, 0, buffer.Length);
//error function codes will be: (original function code) | (0x80)
if ((buffer[7] & 0x80) > 0)
{
throw new Exception();
}
}
public override ModbusTCPMessage Process(IMemoryModel memory)
{
int address = Int16Extensions.FromBytes(PDU.Data.First(), PDU.Data.Skip(1).First());
int length = Int16Extensions.FromBytes(PDU.Data.Skip(2).First(), PDU.Data.Skip(3).First());
try
{
var values = memory.Read4x(address, length);
ProtocolDataUnit pdu = PDU.ValidResponse(
new byte[]
{ (byte)(values.Count() * 2) }
.Concat(values.SelectMany(v => v.GetBytes())));
ModbusTCPMessage reply = Create(
MBAP.Create((byte)(pdu.GetBytes().Count() + 1), ApplicationHeader.UnitID),
pdu);
return(reply);
}
catch
{
ProtocolDataUnit pdu = PDU.ErrorResponse(new byte[] { 0x01 });
ModbusTCPMessage reply = Create(
MBAP.Create((byte)(pdu.GetBytes().Count() + 1), ApplicationHeader.UnitID),
pdu);
return(reply);
}
}
public static ModbusTCPMessage Create(MBAP appHeader, ProtocolDataUnit pdu)
{
switch (pdu.FunctionCode)
{
case ModbusFunctionCodes.ReadHoldingRegisters:
return(new ReadRegistersMessage(appHeader, pdu));
case ModbusFunctionCodes.PresetMultipleRegisters:
return(new WriteHoldingRegistersMessage(appHeader, pdu));
default:
return(new ModbusTCPMessage(appHeader, pdu));
}
}
public override ModbusTCPMessage Process(IMemoryModel memory)
{
try
{
int address = StartAddress();
var values = ParseValues();
memory.Write4x(address, values);
var pdu = PDU.ValidResponse(((Int16)values.Count()).GetBytes());
var reply = Create(
MBAP.Create((byte)(pdu.GetBytes().Count() + 1), ApplicationHeader.UnitID),
pdu);
return(reply);
}
catch
{
var pdu = PDU.ErrorResponse(new byte[] { 0x01 });
ModbusTCPMessage reply = Create(
MBAP.Create((byte)(pdu.GetBytes().Count() + 1), ApplicationHeader.UnitID),
pdu);
return(reply);
}
}
public ReadRegistersMessage(MBAP appHeader, ProtocolDataUnit pdu)
: base(appHeader, pdu)
{
}
protected ModbusTCPMessage(IEnumerable <byte> messageBuffer)
{
ApplicationHeader = MBAP.ParseFromMessage(messageBuffer);
PDU = new ProtocolDataUnit(messageBuffer);
}
protected ModbusTCPMessage(MBAP appHeader, ProtocolDataUnit pdu)
{
ApplicationHeader = appHeader;
PDU = pdu;
}
public WriteHoldingRegistersMessage(MBAP appHeader, ProtocolDataUnit pdu)
: base(appHeader, pdu)
{
}
