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MELSEC-Q
11 TROUBLESHOOTING
Occurrence
Error
Code
Error Name
Description
Lit LED
Corrective Action
1) 2) 3) 4) 5)
73CC
H
In the offline mode,
MODBUS
R
device
assignment parameter setting
request (Y8) was turned on.
COM.ERR.
Do not turn on MODBUS
R
device assignment parameter
setting request (Y8) in the offline
mode.
73CD
H
Offline mode
error
In the offline mode, PING test
execution request (Y1C) was
turned on.
COM.ERR.
Do not turn on PING test
execution request (Y1C) in the
offline mode.
73D0
H
As the TCP connection was
cut off from the target device,
the slave function of the
QJ71MT91 could not send a
response message.
COM.ERR.
• Check whether the operation
status of the target device is
normal or not.
• Check the line status for an
error.
73D1
H
Response
message
transmission
failure
As the TCP connection was
cut off from the target device,
the response message could
not be returned via GX
Developer connection.
COM.ERR.
• Check whether the operation
status of the target device is
normal or not.
• Check the line status for an
error.
73D2
H
Preferred
connection
count over
error
TCP connections exceeding
the number preset in the
preferred node specification
was attempted to be
established.
COM.ERR.
• Increase the maximum number
of TCP connections with the
target node in the preferred
node specification.
• Decrease the number of
connections simultaneously
used with the target node.
73D3
H
Response
message
transmission
failure
As the TCP connection was
cut off from the target device,
the response message via GX
Developer connection could
not be returned.
COM.ERR.
• Check whether the operation
status of the target device is
normal or not.
• Check the line status for an
error.
The send/receive processing
was forcibly interrupted by the
basic parameter setting
processing.
COM.ERR.
Perform the basic parameter
setting processing after the
send/receive processing is over.
73D4
H
An error occurred in the TCP
connection and the
send/receive processing was
forcibly interrupted.
COM.ERR.
• Retry after a little while.
• Check whether the operation
status of the target device is
normal or not.
• Check the line status for an
error.
73D5
H
Send/receive
processing
interruption
As the TCP connection was
being closed, the send/receive
processing was interrupted.
COM.ERR.
• If this occurs at execution of the
dedicated instruction, set “TCP
connection is not closed after
instruction completion” in the
close option of the execution
type.
• If the number of connections
used exceeds the maximum
(64), bring it within the range.
• 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.
(Continued on next page)