Serial Interface (Modbus RTU)
136 M-Max Series Adjustable Frequency Drive MN04020003E—October 2013 www.eaton.com
Data Storage with Modbus
The information is stored in one input and one holding register.
The registers are the memory location of the data. The memory size of each register is
1 word.
Modbus-Register-Mapping
The register mapping enables the processing in MMX of the content listed in the following
table via Modbus RTU.
Each content in this table is assigned an ID number (abbreviation of the register numbers).
This ID number is used in M-Max for the communication with Modbus RTU.
Example: Control word (ID 2001)
With some PLC manufacturers, the interface driver for Modbus RTU communication may
contain an offset of +1 (the ID to be used would then be 2000 instead of 2001).
When processing values, the comma is not included, for example, the motor current (ID 2106)
in the display of the MMX is shown as 0.35 A but is transferred via Modbus as 0023 (hex)
(0035 [dec]).
Register Numbers Type Name
30001–39999 Read only (ro = read only) Input-register
40001–49999 Read/write (rw = Read/write) Holding register
Group Register Numbers ID Range Assignment of the ID Numbers
Display values 40001–40098 (30001–30098) 1...98 Parameter list: (see “Appendix A” starting on
Page 142)
Failure code 40099 (30099) 99 Error list: (see “Error and Warning Messages” starting
on Page 56)
Parameters 40101–40999 (30101–30999) 101...1999 Parameter list: (see “Appendix A” starting on
Page 142)
Input process data 42001–42099 (32001–32099) 2001...2099 (See Page 137)
Output process data 42101–42199 (32101–32199) 2101...2199 (See Page 138)
Value
ID Register Numbers
2001 32001/42001
Application Communication of Modbus RTU Memory location of the data
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