Frame Input
Enter the Modbus frame bytes (without CRC) as hex pairs. The CRC will be appended.
Spaces or no spaces both accepted
e.g.
01 03 00 00 00 0A or 010300000A
0 bytes
Quick Examples
Modbus RTU Function Code Reference
| FC (hex) | Function | Request structure (after device addr) |
|---|---|---|
| 01 | Read Coils | Start addr (2B) + Quantity (2B) |
| 02 | Read Discrete Inputs | Start addr (2B) + Quantity (2B) |
| 03 | Read Holding Registers | Start addr (2B) + Quantity (2B) |
| 04 | Read Input Registers | Start addr (2B) + Quantity (2B) |
| 05 | Write Single Coil | Coil addr (2B) + Value (FF00=ON, 0000=OFF) |
| 06 | Write Single Register | Register addr (2B) + Value (2B) |
| 0F | Write Multiple Coils | Start addr + Qty + Byte count + Data |
| 10 | Write Multiple Registers | Start addr + Qty + Byte count + Data |
| 2B / 0E | Read Device Identification | MEI type (0E) + Read code + Object id |
CRC is always appended as 2 bytes: CRC_LOW then CRC_HIGH (little-endian).