Exceptional Responses - Hitachi WJ Series User Manual

Chapter 11
11.2.9

Exceptional Responses

 If an error occurs in the query, an exceptional response is returned.
A
 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.
 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.
 Exception code details
Code
01h An unsupported function was specified.
02h The specified address does not exist.
03h The specified data is in an unacceptable format.
21h 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.
22h
・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.
23h Writing to the read-only holding register or coil was performed.
26h 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".
27h
(Example) "Output-frequency setting or monitor [F001]" is "2 register length parameter" of
31h
Errors related to Modbus mapping function. For details, refer to "11.3 Modbus Mapping
Function".
32h
Field Configuration
Slave address
Function code
Exception code
CRC-16
Function code
Query
01h
03h
05h
06h
0Fh
10h
17h
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.
11-2-11
RS485 Communication
Exceptional
response
81h
83h
85h
86h
8Fh
90h
97h
Description