SMAX MODBUS®
NOTE
Please note that here follows the list the exception codes indicated by MODBUS
but not necessarily supported by the manufacturer.
MODBUS Exception codes
Code Name
Meaning
01
ILLEGAL FUNCTION
The function code received in the query is not an
allowable action for the server. This may be
because the function code is only applicable to
newer devices, and was not implemented in the
unit selected. It could also indicate that the
server is in the wrong state to process a request
of this type, for example because it is not
configured and is being asked to return register
values.
02
ILLEGAL DATA ADDRESS
The data address received in the query is not an
allowable address for the server. More
specifically, the combination of reference number
and transfer length is invalid. For a controller
with 100 registers, the PDU addresses the first
register as 0, and the last one as 99. If a request
is submitted with a starting register address of
96 and a quantity of registers of 4, then this
request will successfully operate (address-wise at
least) on registers 96, 97, 98, 99. If a request is
submitted with a starting register address of 96
and a quantity of registers of 5, then this request
will fail with Exception Code 0x02 “Illegal Data
Address” since it attempts to operate on registers
96, 97, 98, 99 and 100, and there is no register
with address 100.
03
ILLEGAL DATA VALUE
A value contained in the query data field is not
an allowable value for server. This indicates a
fault in the structure of the remainder of a
complex request, such as that the implied length
is incorrect. It specifically does NOT mean that a
data item submitted for storage in a register has
a value outside the expectation of the
application program, since the MODBUS protocol
is unaware of the significance of any particular
value of any particular register.
04
SERVER DEVICE FAILURE
An unrecoverable error occurred while the server
was attempting to perform the requested action.
MAN SMAX MB E 1.2
Programming parameters
75 of 84
