11 - 36 11 - 36
MELSEC-Q
11 TROUBLESHOOTING
Occurrence
Error
Code
Error Name
Description
Lit LED
Corrective Action
1) 2) 3) 4) 5)
7472
H
IP address
setting error
The host address bits of the IP
address of the request
message transmission
destination are all "0" or all "1".
COM.ERR.
Correct the target IP address set
to the dedicated instruction's
control data or automatic
communication parameter.
7473
H
Connection not
open
• The connection not open was
used to send data.
• The connection used to send
data was already closed.
COM.ERR.
• Check whether the operation
status of the target device is
normal or not.
• Check the line status for an
error.
• Retry after a little while.
7474
H
7475
H
TCP
connection
forcibly
disconnected
The TCP connection was
disconnected forcibly from the
target device.
(This error may be ignored
when no problems arise from
this error.)
COM.ERR.
• Check whether the operation
status of the target device is
normal or not.
• Check the line status for an
error.
• As the line may be busy, retry
after a little while.
7480
H
to
75FF
H
System error
The OS of the QJ71MT91
detected error.
COM.ERR.
Counter the problem in the
following procedure.
• Check whether or not the
QJ71MT91, power supply
module and CPU module are
mounted correctly on the base
unit.
• Check whether or not the
operating environment of the
system is within the range of
general specifications of the
CPU module.
• Check whether the power
capacity is sufficient or not.
• Check the QJ71MT91, CPU
module and base unit to see if
the hardware is normal
according to the manual of each
module.
If the module is faulty, please
contact your local Mitsubishi
service center or representative
for repair.
• If the problem cannot be
resolved in the above steps,
please consult your local
Mitsubishi service center or
representative, explaining a
detailed description of the
problem.
REMARK
(1) Refer to Section 11.3.1 for the error code storage areas.
(2) Refer to Chapter 7 for details of the parameter setting ranges, etc.