Troubleshooting For Modbus Mapping Function - Omron MX2 Series User Manual

8 Communications Functions
8-7-4

Troubleshooting for Modbus Mapping Function

If there is any setting error for the Modbus mapping function, the inverter will display an exception
response during Modbus communication.
In this case, check the exception code for the exception response.
Below are exception codes associated with exception response and the Modbus mapping function set-
ting errors.
For details on other exception codes, refer to 8-5-9 Exception Response on page 8-20.
Exception response for erroneous setting
The function code for an exception response is the sum of the executed function code and 80 hex.
Check the error condition with the exception code.
Response
Slave address
Function code
Exception code
Error check (CRC-16)
Exception code
31 hex
32 hex
8 - 28
Error condition
• The external address is set to other than
0000 and the internal address is not
changed from 0000.
• The internal address has a double-word
register address.
• The set internal address does not exist.
• The external address overlaps.
• When the external address overlaps with
double-word data in the Modbus register
inside the inverter, the inverter received a
command to a non-overlapping address,
which has double-word data.
Multi-function Compact Inverter 3G3MX2-V1 User's Manual (I585-E1)
Countermeasure
• Set the internal address other than 0000.
• Use a compressed single-word register.
• Set the internal address correctly.
• Set the external address so that it does
not overlap.
• The Modbus registers inside the inverter
that overlap with the external address
specified by the Modbus mapping function
are disabled.
For double-word data, both registers are
disabled.
Review the external communications, or
set the Modbus mapping function for that
address.