public void WriteHoldingRegisters(byte unitID, ushort registerBaseAddress, ushort[] values)
{
if ((11 + (values.Length * 2)) > ApplicationDataUnit.maxADU)
{
throw new ArgumentException("Too many values");
}
ApplicationDataUnit aduRequest = new ApplicationDataUnit();
aduRequest.TransactionID = transactionID++;
aduRequest.Length = (ushort)(7 + (values.Length * 2));
aduRequest.UnitID = unitID;
aduRequest.FunctionCode = (byte)FunctionCode.PresetMultipleRegisters;
aduRequest.Payload[0] = (byte)(registerBaseAddress >> 8);
aduRequest.Payload[1] = (byte)(registerBaseAddress & 0x00FF);
aduRequest.Payload[2] = (byte)(((ushort)values.Length) >> 8);
aduRequest.Payload[3] = (byte)(((ushort)values.Length) & 0x00FF);
aduRequest.Payload[4] = (byte)(values.Length * 2);
int payloadIndex = 5;
foreach (ushort value in values)
{
aduRequest.Payload[payloadIndex++] = (byte)(value >> 8);
aduRequest.Payload[payloadIndex++] = (byte)(value & 0x00FF);
}
byte[] buffer = new byte[ApplicationDataUnit.maxADU];
aduRequest.CopyADUToNetworkBuffer(buffer);
// send request to Modbus server
tcpClient.GetStream().Write(buffer, 0, ApplicationDataUnit.headerLength + 5 + (values.Length * 2));
// read response
int numBytesRead = tcpClient.GetStream().Read(buffer, 0, ApplicationDataUnit.headerLength + 4);
if (numBytesRead != ApplicationDataUnit.headerLength + 4)
{
throw new EndOfStreamException();
}
ApplicationDataUnit aduResponse = new ApplicationDataUnit();
aduResponse.CopyHeaderFromNetworkBuffer(buffer);
// check for error
if ((aduResponse.FunctionCode & errorFlag) > 0)
{
// read error
int errorCode = tcpClient.GetStream().ReadByte();
if (errorCode == -1)
{
throw new EndOfStreamException();
}
else
{
HandlerError((byte)errorCode);
}
}
// check address written
if ((buffer[8] != (registerBaseAddress >> 8)) &&
(buffer[9] != (registerBaseAddress & 0x00FF)))
{
throw new Exception("Incorrect base register returned");
}
// check number of registers written
if ((buffer[10] != (((ushort)values.Length) >> 8)) &&
(buffer[11] != (((ushort)values.Length) & 0x00FF)))
{
throw new Exception("Incorrect number of registers written returned");
}
}
public void WriteCoil(byte unitID, ushort coilAddress, bool set)
{
ApplicationDataUnit aduRequest = new ApplicationDataUnit();
aduRequest.TransactionID = transactionID++;
aduRequest.Length = 6;
aduRequest.UnitID = unitID;
aduRequest.FunctionCode = (byte)FunctionCode.ForceSingleCoil;
aduRequest.Payload[0] = (byte)(coilAddress >> 8);
aduRequest.Payload[1] = (byte)(coilAddress & 0x00FF);
aduRequest.Payload[2] = (byte)(set ? 0xFF : 0x0);
aduRequest.Payload[3] = 0x0;
byte[] buffer = new byte[ApplicationDataUnit.maxADU];
aduRequest.CopyADUToNetworkBuffer(buffer);
// send request to Modbus server
tcpClient.GetStream().Write(buffer, 0, ApplicationDataUnit.headerLength + 4);
// read response
int numBytesRead = tcpClient.GetStream().Read(buffer, 0, ApplicationDataUnit.headerLength + 4);
if (numBytesRead != ApplicationDataUnit.headerLength + 4)
{
throw new EndOfStreamException();
}
ApplicationDataUnit aduResponse = new ApplicationDataUnit();
aduResponse.CopyHeaderFromNetworkBuffer(buffer);
// check for error
if ((aduResponse.FunctionCode & errorFlag) > 0)
{
// read error
int errorCode = tcpClient.GetStream().ReadByte();
if (errorCode == -1)
{
throw new EndOfStreamException();
}
else
{
HandlerError((byte)errorCode);
}
}
// check address written
if ((buffer[8] != (coilAddress >> 8)) &&
(buffer[9] != (coilAddress & 0x00FF)))
{
throw new Exception("Incorrect coil register returned");
}
// check flag written
if ((buffer[10] != (set ? 0xFF : 0x0)) &&
(buffer[11] != 0x0))
{
throw new Exception("Incorrect coil flag returned");
}
}
public byte[] ReadRegisters(byte unitID, FunctionCode function, ushort registerBaseAddress, ushort count)
{
// check funtion code
if ((function != FunctionCode.ReadInputRegisters) && (function != FunctionCode.ReadHoldingRegisters))
{
throw new ArgumentException("Only Input registers or holding registers can be read");
}
ApplicationDataUnit aduRequest = new ApplicationDataUnit();
aduRequest.TransactionID = transactionID++;
aduRequest.Length = 6;
aduRequest.UnitID = unitID;
aduRequest.FunctionCode = (byte)function;
aduRequest.Payload[0] = (byte)(registerBaseAddress >> 8);
aduRequest.Payload[1] = (byte)(registerBaseAddress & 0x00FF);
aduRequest.Payload[2] = (byte)(count >> 8);
aduRequest.Payload[3] = (byte)(count & 0x00FF);
byte[] buffer = new byte[ApplicationDataUnit.maxADU];
aduRequest.CopyADUToNetworkBuffer(buffer);
// send request to Modbus server
tcpClient.GetStream().Write(buffer, 0, ApplicationDataUnit.headerLength + 4);
// read response header from Modbus server
int numBytesRead = tcpClient.GetStream().Read(buffer, 0, ApplicationDataUnit.headerLength);
if (numBytesRead != ApplicationDataUnit.headerLength)
{
throw new EndOfStreamException();
}
ApplicationDataUnit aduResponse = new ApplicationDataUnit();
aduResponse.CopyHeaderFromNetworkBuffer(buffer);
// check for error
if ((aduResponse.FunctionCode & errorFlag) > 0)
{
// read error
int errorCode = tcpClient.GetStream().ReadByte();
if (errorCode == -1)
{
throw new EndOfStreamException();
}
else
{
HandlerError((byte)errorCode);
}
}
// read length of response
int length = tcpClient.GetStream().ReadByte();
if (length == -1)
{
throw new EndOfStreamException();
}
// read response
byte[] responseBuffer = new byte[length];
numBytesRead = tcpClient.GetStream().Read(responseBuffer, 0, length);
if (numBytesRead != length)
{
throw new EndOfStreamException();
}
return(responseBuffer);
}
