11 - 6 11 - 6
MELSEC-Q
11 TROUBLESHOOTING
No.
Symptom
Check Item
Corrective Action
Reference
Section
Check if the INIT. LED is on.
Refer to "INIT. LED does not turn on.".
This section
(1)-4
Check if the MODBUS
R
device
assignment parameter setting existence
(XA) is on.
Refer to "MODBUS
R
device assignment
parameter setting existence (XA) does
not turn on.".
This section
(2)-11
Check whether the basic parameters
were re-set during reception of a request
message.
(The slave function stops when the basic
parameters are re-set.)
Restart the automatic communication
function after basic parameter re-setting
is completed.
Section 7.2
Check whether the QJ71MT91 has
returned an exception code or not.
Confirm the exception code and take
corrective action.
Section 11.3.2
Refer to the error log area (0CFE
H
to
0DFF
H
) and confirm the error code.
Take the corresponding corrective
action.
Section 11.3
Is the request message sent to the
QJ71MT91 correct?
Check the following for the message
length.
• The application data unit length in
Ethernet frame is 6 or more (From
"Transaction ID" to "Message length"
in MBAP header).
• The MBAP header 6 equals
the application data unit length in
Ethernet frame.
Correct the request message issued by
the master.
Chapter 4
3 Slave function of
QJ71MT91 does
not return
response
message to
request message.
Refer to "Communication with target device cannot be made even though each
parameter setting is completed.".
This section
(3)-6
Check if the INIT. LED is on.
Refer to "INIT. LED does not turn on.".
This section
(1)-4
When using the TCP protocol, check
whether the set number of TCP
connections for GX Developer
connection is 0 or not.
Set the necessary number of TCP
connections for GX Developer
connection (0030
H
), and re-set the basic
parameter.
Section 7.2.3
Check the GX Developer connection
setup screen settings.
Correct the GX Developer connection
setup screen settings if it has a problem.
4 GX
Developer
cannot be
connected.
Refer to "Communication with target device cannot be made even though each
parameter setting is completed.".
This section
(3)-6
Refer to the error log area (0CFE
H
to
0DFF
H
) and confirm the error code.
Take the corresponding corrective
action.
Section 11.3
5 Error log has
errors.
Refer to "Communication with target device cannot be made even though each
parameter setting is completed.".
This section
(3)-6