Mitsubishi Electric MELSEC iQ-R-R00CPU User Manual page 755

Error Error name Error details and cause
code
3741H Redundant • Both systems were set as system
system error A or system B at start-up.
• The CPU module waiting for a
start-up of the other system
detected that the system A/B
setting is not set to the CPU
module of the other system.
3742H Redundant • The systems were started without
system error system A/B setting.
3743H Redundant • The system setting (system A or
system error B) was not determined.
3744H Redundant • Both systems are set as control
system error systems. (The error is detected in
the system B (control system).)
3745H Redundant • The systems were started with
system error one CPU module set to redundant
mode and the other CPU module
set to process mode.
• The systems were started in a
state where the CPU modules with
firmware versions that cannot be
used together are mounted.
• The systems were started with the
Process CPU and the SIL2
Process CPU.
3746H Tracking • Data communications with the
communications other system could not be
disabled performed within the period of
time set in the CPU parameters
("Other System Start-up Timeout
Setting").
Stop/ Action
continue
Stop • Set one system as system A and the
other system as system B by
performing online operation. Then,
restart the CPU modules in both
systems.
• Set system A or B to the CPU module
with no system setting, and restart the
CPU modules in both systems.
Stop • Set one system as system A and the
other system as system B by
performing online operation. Then,
restart the CPU modules in both
systems. If the same error code is
displayed again, the possible cause is
a hardware failure of the CPU module,
redundant function module, or tracking
cable. Please consult your local
Mitsubishi representative.
Stop • Set one system as system A and the
other system as system B by
performing online operation. Then,
restart the CPU modules in both
systems.
Stop • Restart the CPU module in the system
B.
Stop • When using the CPU modules with
firmware versions that cannot be used
together, replace either CPU module
with the one that can be used together
referring to the MELSEC iQ-R Module
Configuration Manual. When using the
Process CPU and the SIL2 Process
CPU together, replace either CPU
module so that the same CPU module
models are used in both systems.
Then, write a project to the CPU
module in process mode or to the one
after replacement and restart the CPU
modules in both systems.
Stop • If the other system CPU module is
powered off, restart the CPU modules
in both systems.
• If a WDT error has occurred in the
other system CPU module, eliminate
the error cause, and restart the system.
• Connect tracking cables securely and
properly to the connectors of the
redundant function modules in both
systems, and restart the CPU
module(s) with the error. (One cable
shall be connected between the IN
connector of the module in system A
and the OUT connector of the module
in system B. The other cable shall be
connected between the OUT connector
of the module in system A and the IN
connector of the module in system B.)
• Set a longer time in the CPU
parameters ("Other System Start-up
Timeout Setting").
• Take measures to reduce noise. If the
same error code is displayed again, the
possible cause is a hardware failure of
the CPU module, redundant function
module, base unit, or tracking cable.
Please consult your local Mitsubishi
representative.
Detailed Diagnostic
information timing
 At power-on,
at reset, at
tracking cable
connection

At power-on,
at RESET

At power-on,
at RESET

At tracking
cable
connection

At power-on,
at RESET
 At power-on,
at RESET
APPX
753
Appendix 1 Error Codes
A