Mitsubishi FX2-16E series, User Manual

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FX
3U
Series Programmable Controllers
User’s Manual - Hardware Edition
277
14 Test Operation, Adjustment, Maintenance and Troubleshooting
14.5 Troubleshooting with LEDs
11
Hi
gh
-Speed
Counters
12
O
utput W
iri
ng
13
W
iri
ng for
V
ari
ous
Us
es
14
Te
st R
un,
Mai
nten
ance, T
roubl
es
hooti
ng
15
IInput/Output Pow
ered
Exte
nsi
on U
nit
s
16
Input/O
utput
Extens
ion
Bl
ock
s
17
Extension Power Suppl
y
Un
it
18
Other Extens
ion
Uni
ts an
d
Opti
ons
19
D
isplay M
od
ule
20
Te
rminal
Bl
oc
k
14.5.3 ERROR LED [on/flashing/off]
State of
LED
State of PLC Remedies
On
A watchdog timer error may have
occurred, or the hardware of the PLC
may be damaged.
1) Stop the PLC, and re-apply power.
If ERROR LED goes off, a watchdog timer error may have
occurred. Take any of the following measures.
- Review the program.
The maximum value (D8012) of the scan time should not
exceed the setting (D8000) of the watchdog timer.
- Check that the input used for input interruption or pulse
catch is not being abnormally turned on and off in one scan.
- Check that the frequency of the pulse (duty of 50%) input to
the high-speed counter does not exceed the specified
range.
- Add the WDT instructions.
Add some WDT instructions to the program, and reset the
watchdog timer several times in one scan.
- Change the setting of the watchdog timer.
Change the watchdog timer setting (D8000) in the program
so that the setting is larger than the maximum value of the
scan time (D8012).
2) Remove the PLC and supply power to it from another power
supply on a desk.
If the ERROR LED goes off, noise may have affected the
PLC. Take the following measures.
- Check the ground wiring, and reexamine the wiring route
and installation location.
- Fit a noise filter onto the power supply line.
3) If the ERROR LED does not go off even after the measures
stated in (1) and (2) are taken, consult your local Mitsubishi
Electric representative.
Flashing
One of the following errors has
occurred in the PLC.
• Parameter error
• Syntax error
• Ladder error
Perform PLC diagnosis and program check with the
programming tool.
For the remedies, refer to Section 14.6 "Judgment by Error
Codes and Representation of Error Codes".
Off
No errors that stop the PLC have
occurred.
If the operations of the PLC are abnormal, perform PLC
diagnosis and program check with the programming tool.
An I/O error, Comms.error or Runtime error may have occurred.