Request PDU
Function code
1 byte
0x06
Register address
2 bytes
0x0000 to 0xFFFF
Register value
2 bytes
0x0000 to 0xFFFF
Response PDU
Function code
1 byte
0x06
Register address
2 bytes
0x0000 to 0xFFFF
Register value
2 bytes
0x0000 to 0xFFFF
Exception Response PDU
Error code
1 byte
0x86 (=0x06 + 0x80)
Exception code
1 byte
01 or 02 or 03 or 04
Here is an example of a request to write the value 05 DC hex (= 1500 dec) in the
parameter (register 8).
Request
Response
Field name
(Hex)
Field name
(Hex)
Function
06
Function
06
Register address Hi
00
Register address Hi
00
Register address Lo
07
Register address Lo
07
Register value Hi
05
Register value Hi
05
Register value Lo
DC
Register value Lo
DC
As you can see in the table, the value 05 DC hex, i.e. 1500 in decimal notation, is
set in the
parameter (register 8).
MAN RD6 MB E 1.1
Modbus® interface
58 of 92
RD6 Modbus®