Exception Code List - Mitsubishi QJ71MT91 User Manual

11 TROUBLESHOOTING

11.3.2 Exception code list

Exception
Error Name
Code
01 Illegal function
H
Illegal data
02
H
address
03 Illegal data value
H
Slave device
04
H
failure
05 Acknowledge
H
06 Slave busy
H
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An exception code is an error code commonly used for the MODBUS
is embeded into a response message when the slave returns an exception response in
reply to a request message from the master.
(1) When the QJ71MT91 is a master
When the QJ71MT91 (master) has received an exception code from the target
device (slave), take corrective actions referring to the manual for the target
device (slave).
(2) When the QJ71MT91 is a slave
When the target device (master) has received an exception code from the
QJ71MT91 (slave), take corrective actions referring to the following.
(a) Exception code storage location
If the processing in the slave results in error completion, the exception code
can be confirmed in the error log area (address: CFE
buffer memory.
(b) Exception code list
The following is a list of exception codes used when the QJ71MT91 is a
slave.
Description
The slave (QJ71MT91)
received an unsupported
function code.
The specified address of the
MODBUS R device is
abnormal.
The contents of the data part of
the request message are
abnormal.
A fatal error occurred while the
slave (QJ71MT91) was
attempting to perform the
requested action and the
processing was impossible.
As the slave is executing other
processing, a long duration of
time is required for completion
of the request message
processing.
As the slave is executing other
processing, the request
message processing cannot be
executed.
Corrective Action
Target device (Master side)
Confirm the function code
supported by QJ71MT91, and
review the request message to
be sent.
Confirm the MODBUS R device
type and size supported by
QJ71MT91, and review the
specified address of the request
message to be sent.
Review the data part of the
request message.
Review the data part of the
request message.
Not issued by the slave function of the QJ71MT91.
Retry after a little while.
MELSEC-Q
protocols, which
R
to DFF ) of the
H H
QJ71MT91 (Slave side)
Remove the error factor in the
QJ71MT91.
If the QJ71MT91 issued this
code, confirm the error code
stored in the error log area
(Refer to Section 11.3.1 (8)) and
take corrective action.
If the QJ71MT91 issued this
code, the number of
simultaneously acceptable
request message (64) is
exceeded.
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