/// <summary>
/// Gets the element value according to its type, converted to double.
/// </summary>
public double GetElemVal(int elemIdx)
{
Elem elem = Elems[elemIdx];
byte[] elemData = ElemData[elemIdx];
byte[] buf;
// order bytes if needed
if (elem.ByteOrder == null)
{
buf = elemData;
}
else
{
buf = new byte[elemData.Length];
ModbusUtils.ApplyByteOrder(elemData, buf, elem.ByteOrder);
}
// calculate value
switch (elem.ElemType)
{
case ElemType.UShort:
return(BitConverter.ToUInt16(buf, 0));
case ElemType.Short:
return(BitConverter.ToInt16(buf, 0));
case ElemType.UInt:
return(BitConverter.ToUInt32(buf, 0));
case ElemType.Int:
return(BitConverter.ToInt32(buf, 0));
case ElemType.ULong: // possible data loss
return(BitConverter.ToUInt64(buf, 0));
case ElemType.Long: // possible data loss
return(BitConverter.ToInt64(buf, 0));
case ElemType.Float:
return(BitConverter.ToSingle(buf, 0));
case ElemType.Double:
return(BitConverter.ToDouble(buf, 0));
case ElemType.Bool:
return(buf[0] > 0 ? 1.0 : 0.0);
default:
return(0.0);
}
}
/// <summary>
/// Initializes the request PDU and calculates the response length.
/// </summary>
public override void InitReqPDU()
{
if (DataBlock == DataBlock.Custom)
{
// build PDU for custom command
int dataLength = Data == null ? 0 : Data.Length;
ReqPDU = new byte[1 + dataLength];
ReqPDU[0] = FuncCode;
if (dataLength > 0)
{
Buffer.BlockCopy(Data, 0, ReqPDU, 1, dataLength);
}
RespPduLen = ReqPDU.Length; // assuming echo
}
else if (Multiple)
{
// build PDU for WriteMultipleCoils and WriteMultipleRegisters commands
int quantity; // quantity of registers
int dataLength; // data length in bytes
if (DataBlock == DataBlock.Coils)
{
quantity = ElemCnt;
dataLength = (ElemCnt % 8 == 0) ? ElemCnt / 8 : ElemCnt / 8 + 1;
}
else
{
quantity = ElemCnt * ModbusUtils.GetQuantity(ElemType);
dataLength = quantity * 2;
}
ReqPDU = new byte[6 + dataLength];
ReqPDU[0] = FuncCode;
ReqPDU[1] = (byte)(Address / 256);
ReqPDU[2] = (byte)(Address % 256);
ReqPDU[3] = (byte)(quantity / 256);
ReqPDU[4] = (byte)(quantity % 256);
ReqPDU[5] = (byte)dataLength;
ModbusUtils.ApplyByteOrder(Data, 0, ReqPDU, 6, dataLength, ByteOrder, false);
// set response length
RespPduLen = 5;
}
else
{
// build PDU for WriteSingleCoil and WriteSingleRegister commands
int dataLength = DataBlock == DataBlock.Coils ? 2 : ModbusUtils.GetDataLength(ElemType);
ReqPDU = new byte[3 + dataLength];
ReqPDU[0] = FuncCode;
ReqPDU[1] = (byte)(Address / 256);
ReqPDU[2] = (byte)(Address % 256);
if (DataBlock == DataBlock.Coils)
{
ReqPDU[3] = Value > 0 ? (byte)0xFF : (byte)0x00;
ReqPDU[4] = 0x00;
}
else
{
byte[] data = dataLength == 2 ?
new byte[] // standard Modbus
{
(byte)(Value / 256),
(byte)(Value % 256)
} :
Data;
ModbusUtils.ApplyByteOrder(data, 0, ReqPDU, 3, dataLength, ByteOrder, false);
}
// set response length
RespPduLen = ReqPDU.Length; // echo
}
}