Chapter 11 RS485 Communication
11-2-11
11.2.9 Exceptional Responses
If an error occurs in the query, an exceptional response is returned.
For non-broadcast queries, the master is requesting a response. The inverter must return a
response corresponding to the query, but if an error occurs in the query, it will return an
exceptional response.
The exceptional response has the field configuration shown in the table below.
Field Configuration
Details of the field configuration are shown in the table below. The function code is the value
added to the query by 80h in the exceptional response. The exception code indicates the cause
of the exceptional response.
Function code
An unsupported function was specified.
The specified address does not exist.
The specified data is in an unacceptable format.
When writing to the holding register, the data is out of the setting range.
The inverter does not permit the function.
・An attempt was made to change the holding register of change prohibition during operation.
・Writing is performed to the holding register which is set to soft lock.
・An attempt was made to change an I/O pin function that cannot be changed.
・An attempt was made to change the contact a/b of the terminal to which the input terminal
function "Reset [RS]" was assigned.
・Attempt to write to register when auto-tuning is enabled.
・An attempt was made to write to the lock target register while setting the password; and so on.
Writing to the read-only holding register or coil was performed.
Writing was performed during data writing or data initialization.
Only the higher register of "2 register length parameter" was accessed.
In Modbus communication of WJ-C1, there is a holding register with restrictions when accessing
as "2 register length parameter" large data that cannot fit in 1 word. For the target register of "2
register length parameter", see "18.2 List of Parameters and Modbus Holding Registers".
(Example) "Output-frequency setting or monitor [F001]" is "2 register length parameter" of
register numbers 0001h and 0002h. Reading/writing only 0002h of the lower word
is possible for this register, but reading/writing only the upper word becomes an
error.
Errors related to Modbus mapping function. For details, refer to "11.3 Modbus Mapping
Function".
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