FX1N Series Programmable Controllers Diagnostics 7.
7-2
7.2 ERROR LED ON (CPU ERROR)
Fault
ERROR 
LED ON
Remedy
Reset PLC. 
Power 
OFF,ON 
and trigger 
RUN input.
Possible 
results
LED OFF
Has the memory cassette been 
installed or removed while the units 
has still been powered?
LED is lit
Remedy
Possible 
results
LED is lit
Power OFF
Disconnect 
earth/
ground 
terminal
LED is 
flashing
Check for programming error. Ensure the earth/
ground cable is correctly rewired.
Power ON
Remedy
Possible program/scan time error. 
Check D8012 for program scan time, 
(units 0.2 ms must be less than 0.2 s, 
i.e data value <2000).
Possible results
D8012 > D8000
POWER
RUN
ERROR
A
A
B
PC M/C PC M/C PC M/C
99 8
B