8
TROUBLESHOOTING
8.1 Troubleshooting Flow
8.1.1 Flow for the Case where the "MODE" LED is not ON
8
- 4
1
OV
ER
VIE
W
2
SYS
TEM
CONFIGURA
TI
ON
3
TR
AC
KI
N
G
C
ABL
E
4
P
R
OCE
DURE
FO
R
S
TAR
TING
UP
A
RE
DUN
DAN
T
S
Y
S
T
E
M
5
RE
DUNDA
NT S
Y
S
T
E
M
FUNCTIONS
6
RE
DUN
DAN
T
S
Y
S
T
E
M
NE
TW
O
R
K
S
7
PR
OG
R
A
MM
IN
G
CA
UTIO
N
S
8
TR
O
U
BLE
S
HOOTING
8.1.1 Flow for the Case where the "MODE" LED is not ON
Diagram 8.3 is for the case where the "MODE" LED does not turn on when the PLC is
powered on.
* 1 : Relevant to the redundant power supply module.
Diagram 8.3 Flow for the Case where the MODE LED is not On
The "MODE" LED does not light up
The power supply module's
"POWER" LED
Connect GX Developer to the CPU
module.
YES
Lit solid green
YES
Not light or lit solid red
*1
NO
NO
NO
RESET Position
Does the "MODE" LED light up?
NO
YES
YES
Completed
Power supply module hardware fault
Does the "MODE" LED light up?
NO
Neutral position
Replace the power supply module
and confirm the "POWER" LED is lit
Is communication with GX
Developer possible?
Does the "MODE" LED light up?
Perform a PLC diagnostic and troubleshooting
based on the diagnostic results.
Check the wiring and turn on the
power.
QCPU User's Manual
(Hardware Design,
Maintenance and Inspection)
Is the CPU module's
RESET/L.CLR Switch set
to the neutral position?
The following modules may be experiencing
hardware errors.
Confirm operation of a minimum system of the
basic base module with a power supply module
and CPU module installed, and slowly build up
from this.
For modules that are not functioning, please
contact the nearest
Mitsubishi
represenative
, reseller or branch office and
explain the fault symptoms.
1) CPU module
2) Basic base module
3) Network Module
After resetting using the RESET/L. CLR switch,
return the switch to the neutral position.
YES
Is current being
supplied to the power supply
module?
Is the power supply
module cabling
normal?