GN-9289 User Manual
Page 37 of (70)
G-series GN-9289 Modbus TCP_UDP Rev. 1.01.docx
8.2.4.
4 (0x04) Read Input Registers
This function code is used to read from 1 to approx. 125 contiguous input registers in a remote device. The
Request PDU specifies the starting register address and the number of registers. The register data in the
response message are packed as two bytes per register, with the binary contents right justified within each
byte. For each register, the first byte contains the high order bits and the second contains the low order bits.
Request
Field name
Example
Function Code
0x04
Starting Address Hi
0x00
Starting Address Lo
0x00
Quantity of Register Hi
0x00
Quantity of Register Lo
0x02
Response
Field name
Example
Function Code
0x03
Byte Count
0x04
Input Register#0 Hi
0x00
Input Register#0 Lo
0x80
Input Register#1 Hi
0x00
Input Register#1 Lo
0x00
In case of address 0x0000, 0x0001 input register value: 0x0080, 0x0000.
8.2.5.
5 (0x05) Write Single Coil
This function code is used to write a single output to either ON or OFF in a remote device. The requested
ON/OFF state is specified by a constant in the request data field. A value of FF 00 hex requests the output to
be ON. A value of 00 00 requests it to be OFF. All other values are illegal and will not affect the output.
Request
Field name
Example
Function Code
0x05
Output Address Hi
0x10
Output Address Lo
0x01
Output Value Hi
0xFF
Output Value Lo
0x00
Response
Field name
Example
Function Code
0x05
Output Address Hi
0x10
Output Address Lo
0x01
Output Value Hi
0xFF
Output Value Lo
0x00
- Output bit of address 0x1001 turns ON.
