Mitsubishi Electric QJ71MT91 User Manual page 238

11 TROUBLESHOOTING
No. Symptom
1 The systems are
not switched
when
communication
error occurs.
11 - 5
(3) Troubleshooting for system switching in a redundant system
Check Item
Is the QJ71MT91 mounted the
function version D?
Has the QJ71MT91 issued a system
switching request to the control
system CPU module?
Is the system switching setting
enabled?
Is any Ethernet cable disconnected
when linkup has not yet been
performed after system startup?
Is the setting value of the
disconnection detection time correct?
Is the setting value in TCP ULP timer
correct?
Is the KeepAlive enabled?
Is the setting value in the KeepAlive
start timer correct?
Is the setting value in the KeepAlive
interval timer correct?
Is the TCP connection open?
Corrective Action
Replace the QJ71MT91 with the
one having the function version D
or later
Use SD1590 of the control system
CPU module to check if the
QJ71MT91 has issued a system
switching request.
Check if the system switching
cause settings (b1 to b3) in the
intelligent function module switch
5 (redundant settings) are
enabled.
Check the wiring status of the
Ethernet cable.
(The system switching due to the
disconnection detection can be
detected after linkup was
performed normally.)
Review the setting value of the
disconnection detection time (b8
to b15) in the intelligent function
module switch 5 (redundant
settings).
Review the TCP ULP timer value
of the basic parameter.
Set the KeepAlive of the basic
parameter to "Used" to switch the
systems by timeout detection of
KeepAlive.
Review the KeepAlive start timer
value of the basic parameter.
Review the KeepAlive interval
timer value of the basic parameter.
Review the wiring and
communication setting and open
the TCP connection.
(The system switching due to the
communication error can be
detected after the TCP connection
was opened normally.)
MELSEC-Q
Reference
Section
Section 6.6
Section 6.6
Section 7.2
Section 5.4
Section 7.2
Section 5.4
Section 7.2
Section 5.4
Section 7.2
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