comfilehmi:simplemodbus:modbus_code3:index
Function Code 03 : Read Registers
This Function Code reads 1 or more 16-bit words. The example below reads registers 1 ~ 3.
Query:
| Field | Data | Number of Bytes |
|---|---|---|
| Slave Address | 0x03 | 1 |
| Function Code | 0x03 | 1 |
| Start Address HI | 0x00 | 1 |
| Start Address LO | 0x00 | 1 |
| Length HI | 0x00 | 1 |
| Length LO | 0x03 | 1 |
| Error Check | CRC | 2 |
Response: Because the Length field of the query was 3, the response returns 6 bytes.
| Field | Data | Number of Bytes |
|---|---|---|
| Slave Address | 0x03 | 1 |
| Function Code | 0x03 | 1 |
| Byte Count | 0x06 | 1 |
| Data 1 HI | 0xAB | 1 |
| Data 1 LO | 0x67 | 1 |
| Data 2 HI | 0xAB | 1 |
| Data 2 LO | 0x67 | 1 |
| Data 3 HI | 0xAB | 1 |
| Data 3 LO | 0x67 | 1 |
| Error Check | CRC | 2 |
comfilehmi/simplemodbus/modbus_code3/index.txt · Last modified: 2016/12/07 15:41 by COMFILE Technology