/// <summary>
/// Create the bytes-package to request data from the PLC. You have to specify the memory type (dataType),
/// the address of the memory, the address of the byte and the bytes count.
/// </summary>
/// <param name="dataType">MemoryType (DB, Timer, Counter, etc.)</param>
/// <param name="db">Address of the memory to be read</param>
/// <param name="startByteAdr">Start address of the byte</param>
/// <param name="count">Number of bytes to be read</param>
/// <returns></returns>
private static void BuildReadDataRequestPackage(System.IO.MemoryStream stream, DataType dataType, int db, int startByteAdr, int count = 1)
{
//single data req = 12
stream.WriteByteArray(new byte[] { 0x12, 0x0a, 0x10 });
switch (dataType)
{
case DataType.Timer:
case DataType.Counter:
stream.WriteByte((byte)dataType);
break;
default:
stream.WriteByte(0x02);
break;
}
stream.WriteByteArray(Word.ToByteArray((ushort)(count)));
stream.WriteByteArray(Word.ToByteArray((ushort)(db)));
stream.WriteByte((byte)dataType);
var overflow = (int)(startByteAdr * 8 / 0xffffU); // handles words with address bigger than 8191
stream.WriteByte((byte)overflow);
switch (dataType)
{
case DataType.Timer:
case DataType.Counter:
stream.WriteByteArray(Types.Word.ToByteArray((ushort)(startByteAdr)));
break;
default:
stream.WriteByteArray(Types.Word.ToByteArray((ushort)((startByteAdr) * 8)));
break;
}
}
/// <summary>
/// Creates the header to read bytes from the PLC
/// </summary>
/// <param name="amount"></param>
/// <returns></returns>
private static void BuildHeaderPackage(System.IO.MemoryStream stream, int amount = 1)
{
//header size = 19 bytes
stream.WriteByteArray(new byte[] { 0x03, 0x00 });
//complete package size
stream.WriteByteArray(Types.Int.ToByteArray((short)(19 + (12 * amount))));
stream.WriteByteArray(new byte[] { 0x02, 0xf0, 0x80, 0x32, 0x01, 0x00, 0x00, 0x00, 0x00 });
//data part size
stream.WriteByteArray(Types.Word.ToByteArray((ushort)(2 + (amount * 12))));
stream.WriteByteArray(new byte[] { 0x00, 0x00, 0x04 });
//amount of requests
stream.WriteByte((byte)amount);
}
