ProSoft Technology inRAX MVI56E-MNETCR User Manual page 130

Reference
User Manual
If the output address is non-existent in the server device, the server will return
the exception response with the exception code shown (02). This specifies an
illegal data address for the Server.
Modbus Exception Codes
Code Name
01 Illegal Function
02 Illegal Data Address
03 Illegal Data Value
04 Slave Device Failure
05 Acknowledge
06 Slave Device Busy
08 Memory Parity Error
0a Gateway Path Unavailable Specialized use in conjunction with gateways, indicates
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Modbus TCP/IP Multi Client Enhanced Communications Module for Remote Chassis
Meaning
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 unconfigured and is being
asked to return register values.
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, a request with offset 96 and
length 4 would succeed; a request with offset 96 and length
5 will generate exception 02.
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,
because the Modbus protocol is unaware of the
significance of any particular value of any particular
register.
An unrecoverable error occurred while the Server was
attempting to perform the requested action.
Specialized use in conjunction with programming
commands. The Server has accepted the request and is
processing it, but a long duration of time will be required to
do so. This response is returned to prevent a timeout error
from occurring in the Client. The Client can next issue a
poll program complete message to determine if processing
is completed.
Specialized use in conjunction with programming
commands. The Server is engaged in processing a long-
duration program command. The Client should retransmit
the message later when the Server is free.
Specialized use in conjunction with function codes 20 and
21 and reference type 6, to indicate that the extended file
area failed to pass a consistency check. The Server
attempted to read record file, but detected a parity error in
the memory. The Client can retry the request, but service
may be required on the Server device.
that the gateway was unable to allocate an internal
communication path from the input port to the output port
for processing the request. Usually means that the gateway
is misconfigured or overloaded.
MVI56E-MNETCR ♦ ControlLogix Platform
ProSoft Technology, Inc.
June 14, 2011