Serial Interface (Modbus RTU)
M-Max Series Adjustable Frequency Drive
MN04020003E—October 2013 www.eaton.com
141
Function Code 06 (hex): Writing a Holding Register
This function writes the data to a holding register (of
specified register addresses).
Example:
Writing of the control word (BUS) (ID 2001) of an MMX
frequency inverter with the slave address 5.
Master request: 05 06 07D0 0003 C2C8 (hex)
Slave response: 05 06 07D0 0003 C8C2 (hex)
The slave response is a copy of the master request if it is a
normal response.
Function code 06 (hex) can be used for broadcasting.
Function Code 10 (hex): Writing of the Holding Registers
This function writes data to a number of consecutive holding
registers (of specified register addresses).
CAUTION
Although the registers to be written are consecutive, the ID
numbers of the parameter list are not. Only the ID numbers
in the process data list are consecutive.
Example:
Writing of the control word (ID 2001) of the general control
word (ID 2002) and the speed setpoint (ID2003) of an MMX
frequency inverter with the slave address 5.
Master request:
05 10 07D0 0003 06 0001 0000 2710 D125 (hex)
Slave response: 05 10 07D0 0003 8101 (hex)
Function code 10 (hex) can be used for broadcasting.
Hex
Name
05
Slave address
06
Function code (here: Writing of a holding register)
07D0
2000 (dec): The ID number of the written register is
2001 (dec) as the master PLC has an offset of +1
0003
Content (2 bytes) for register 42101:
0000 0000 0000 0011 [bin]
See anticlockwise, RUN
C2C8
CRC
Hex
Name
05
Slave address
06
Function code (here: Writing of a holding register)
07D0
2000 (dec): The ID number of the first requested register
is 2001 (dec) as the master PLC has an offset of +1
0003
Content (2 bytes) for register 42101:
0000 0000 0000 0011 (bin)
See anticlockwise, RUN
C8C2
CRC
Hex
Name
05
Slave address
10
Function code (here: Writing of the holding registers)
07D0
2000 (dec): The ID number of the first written
register is 2001 (dec) as the master PLC has an offset of +1
0003
Total number of requested registers
(42001–42103)
06
Number of consecutive data bytes
(3 registers x 2 bytes = 6 bytes)
0001
Content (2 bytes) for register 42101:
0000 0000 0000 0001 (bin) (Start command)
0000
Content (2 bytes) for register 42102:
0000 (dec) (no content, as not used)
2710
Content (2 bytes) for register 42103:
10.000 (dec) (frequency setpoint = 100.00%)
D125
CRC
Hex
Name
05
Slave address
10
Function code (here: Writing of the holding registers)
07D0
2000 (dec): The ID number of the first written register
is 2001 (dec) as the master PLC has an offset of +1
0003
Total number of requested registers
(42001–42103)
8101
CRC
