User`s manual

Troubleshooting Troubleshooting
11 – 22
11.2.22 When the CPU module does not start
Refer to the following flowchart when the CPU module does not start upon power-on.
* For the Basic model QCPU, check the RUN/STOP/RESET switch of CPU module
The CPU module does not start.
POWER LED off:
refer to section 11.2.4
POWER LED on (red) (redun-
dant power supply modules
only):
refer to section 11.2.6
Does the CPU
module start?
Check the wiring and turn ON all power
supply modules.
Correct the connection of the extension
Cancel the RESET position.
Completed
A hardware fault may have occurred in
any of the following modules:
 Main base unit/extension base unit
 Extension cable
 CPU module
 I/O Module or intelligent function
module
Perform operations in due order, star-
ting with the minimum system where the
power supply module and CPU module
are mounted on the main base unit.
For the module that does not operate,
please consult your local Mitsubishi ser-
vice center or representative, explaining
a detailed discription of the problem.
Is the POWER LED
of the power supply module
lit (green)?
Is the direction of
the exension cable correct?
(OUT –> IN)
Position of the
RESET/L.CLR switch* of
the CPU
NO
NO
NO
NO
NO
NO
other than RESET position
YES
YES
YES
RESET position
YES
YES
YES
Hardware error of power supply module.
Change the power supply module and
check if the LED lights up (green).
NO
YES
NO
YES
Is communication
with programming device
successful?
Perform PLC diagnostics and trouble-
shoot according to the results of the di-
agnosis.
NO
Connect programming device.
Are all power supply
modules turned on? Is the
power supply module
connected correctly?
Does the CPU
module start?
Does the CPU
module start?
Does the CPU
module start?