FC410 with Modbus
Operating Instructions, 02/2016, A5E33120874-AC
149
Exception codes
E
E.1
Exception handling
There is a defined set of exception codes to be returned by slaves in the event of problems.
All exceptions are signalled in the response from the slave by adding 80 hex to the function
code of the request and following this byte by an exception code.
Table E- 1
Exception codes
Exception
code (dec)
Exception text
Description
01
Illegal function
The function code received in the query is not an allowable
action for the slave
02
Illegal data address
The data address received in the query is not an allowable
address for the slave.
03
Illegal data value
A value contained in the query data field is not an allowable
value for the addressed location. This may indicate a fault in
the structure of the remainder of a complex request, such that
the implied length is incorrect or the number of registers is too
high.
04
Slave device failure
The request is for some other reason not acceptable. It may
e.g. indicate that the data value to write is evaluated to be
beyond limits.