====== Function Code 01 : Read Coil ======

This Function Code reads the state of 1 or more bits.  The example below reads coils 1 ~ 8.

Query:

^ Field        ^  Data  ^  Number of Bytes  ^
| Slave Address  | 0x03   |  1      |
| Function Code       | 0x01 |  1      |
| Start Address HI  | 0x00 |  1      |
| Start Address LO  | 0x00 |  1      |
| Length HI      | 0x00 |   1     |
| Length LO      | 0x08 |   1     |
| Error Check       | CRC     |   2      |


Response:

^ Field        ^  Data  ^  Number of Bytes  ^
|Slave Address |0x03 |  1  |
|Function Code |0x01 |  1  |
|Byte Count |0x01 |  1  |
|Data |0x53 |  1  |
|Error Check | CRC |  2  |

비트정보 8 개를 읽어서 한 개의 바이트로 구성한 다음 반환해줍니다..