ReadString

ReadString snippet.cs

        /// <summary>
        /// Read known string from PLC
        /// </summary>
        /// <param name="startAddr">start byte in format DBx.DBBy</param>
        /// <returns>known string</returns>
        public string ReadString(string startAddr)
        {
            if (_plc.IsConnected)
            {
                _plc.ClearLastError();
                // decode db and start byte
                int db = int.Parse(startAddr.Substring(2, startAddr.IndexOf('.') - 2));
                int startByte = int.Parse(startAddr.Substring(startAddr.IndexOf('.') + 4));
                // read string header
                var header = (byte[])_plc.Read(DataType.DataBlock, db, startByte, VarType.Byte, 2);
                // read used bytes as string
                var bytes = new List<byte>();
                if (header[0] != header[1])
                {
                    if (header[1] > 1)
                    {
                        bytes.AddRange((byte[])_plc.Read(DataType.DataBlock, db, startByte + 2, VarType.Byte, header[1] > header[0] ? header[0] : header[1]));
                    }
                    else
                    {
                        if (header[1] > 0)
                        {
                            bytes.Add((byte)_plc.Read(DataType.DataBlock, db, startByte + 2, VarType.Byte, header[1] > header[0] ? header[0] : header[1]));
                        }
                    }
                }
                return System.Text.Encoding.ASCII.GetString(bytes.ToArray(), 0, bytes.Count).Replace("\0", "");
            }
            return default(string);
        }