108
header
address
code
Register address
Setting value
code
Character
:
0
5
0
6
0
2
0
1
0
0
0
3
E
F
CR
LF
ASCII
3A
30
35
30
36
30
32
30
31
30
30
30
33
45
46
0D
0A
VFD can set different delay time for response according to different application.For RTU mode,the actual delay time
for response is 3.5 characters interval at least.For ASCII mode,the actual delay time for response is 1 ms at least.
5. Protocol Function
The main functions of Modbus are read and write parameters.Different function codes need different operation
request.The modbus protocol of VFD support the operations in the following table.
Function code
Meaning
0x03
Read parameters of VFD,including function code parameters,control parameters and status
parameters.
0x06
Rewrite single function code or control parameter with 16bit length,the value of the
parameter can’t be saved after VFD power off.
0x08
Diagnosis.
0x10
Rewrite multiple function code or control parameters,the vaule of the parameters can’t be
saved after VFD power off.
0x41
Rewrite single function code or control parameter with 16bit length,the value
can be saved after VFD power off.
0x42
Manage function code of VFD.
0x43
Rewrite multiple function code or control parameters,the vaule of the parameters can be
saved after VFD power off.
All the function code, control parameters and status parametes of VFD are mapping to the read/write register of
Modbus.The group number of function code is mapping to the high byte of register address and the index address in
the group is mapping to the low byte of register address.The corresponding relationship between group number and
register address is shown in following table.
Group No.
High bye of mapping
address
Group No.
High bye of mapping
address
Group A0
0x00
Group B2
0x0C
Group A1
0x01
Group B3
0x0D
Group A2
0x02
Group B4
0x0E
Group A3
0x03
Group C0
0x14
Group A4
0x04
Group C1
0x15
Group A5
0x05
Group D0
0x1E
Group A6
0x06
Group D1
0x1F
Group A7
0x07
Group D2
0x20
Group A8
0x08
Group U0
0x5A
Group B0
0x0A
Control parameter
0x32
Group B1
0x0B
Status parameter
0x33
For example, the register address of function code A3.02 is 0x0302, and the register address of the first control
parameter (Control command 1) is 0x3200.