public static int ModBus_Expend(byte[] Buf, int Length, ref MB ModBusMsg)
{
int i = 0;
int DataOffSet = 0;
int Cheak;
ModBusMsg.ErrorFlag = (byte)ModBus_SizeError;
if (ModBusMsg.Start != Buf[i++])
{
return(0);
}
if (ModBusMsg.WorkMode == (byte)MasterSlaveMode.WorkMode_Master)//当协议运行为主机模式
{
if (ModBusMsg.MasterAddr != Buf[i++])
{
return(0);
}
if (ModBusMsg.SlaveAddr != Buf[i++])
{
;
}
}
else if (ModBusMsg.WorkMode == (byte)MasterSlaveMode.WorkMode_Slave)//当协议运行在从机模式
{
byte TempAddr = Buf[i++];
if ((TempAddr != ModBusMsg.SlaveAddr) & (TempAddr != BroadAddr))
{
return(0);
}
if (Buf[i++] != ModBusMsg.MasterAddr)
{
return(0);
}
}
ModBusMsg.MsgFlag = Buf[i++];
ModBusMsg.MsgNum = Buf[i++];
ModBusMsg.MsgLength = Buf[i++];
ModBusMsg.MsgLength <<= 8;
ModBusMsg.MsgLength |= Buf[i++];
if (ModBusMsg.MsgLength > 0)
{
ModBusMsg.DataFlag = Buf[i++];
ModBusMsg.DataLength = Buf[i++];
ModBusMsg.DataLength <<= 8;
ModBusMsg.DataLength |= Buf[i++];
DataOffSet = i;
i += ModBusMsg.DataLength;
ModBusMsg.Data = new byte[ModBusMsg.DataLength];
for (int n = 0; n < ModBusMsg.DataLength; n++)
{
ModBusMsg.Data[n] = Buf[DataOffSet++];
}
if (ModBusMsg.MsgLength != (ModBusMsg.DataLength + 3))
{
return(0);
}
}
if (ModBusMsg.CheakMode == CheakMode_Xor)
{
Cheak = Tools.Xor(Buf, i);
if (Cheak != Buf[i])
{
return(0);
}
i++;//xor校验一位
if (ModBusMsg.End != Buf[i++])
{
return(0);
}
// if (i != (Length - 2)) ModBusMsg.ErrorFlag = ModBus_SizeError;//有可能尾部还有其他直接忽略
}
else if (ModBusMsg.CheakMode == CheakMode_Crc)
{
Cheak = Tools.GetCrc16(Buf, i);
//MessageBox.Show(Cheak.ToString("X")); MessageBox.Show(Tools.ByteToInt16(Buf, i, 0).ToString("X"));
if (Cheak != Tools.ByteToInt16(Buf, i, 0))
{
return(0);
}
i += 2;//crc校验2位
if (ModBusMsg.End != Buf[i++])
{
return(0);
}
// if (i != (Length)) return 0;//有可能尾部还有其他直接忽略
}
if (ModBusMsg.End != Buf[ModBusMsg.MsgLength + 9])
{
return(0);
}
if (i != (ModBusMsg.MsgLength + 10))
{
return(0);
}
ModBusMsg.ErrorFlag = ModBus_Ok;
return(DataOffSet);
}