Self-Diagnostic Function and TroubleshootingFP2/FP2SH
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8.1 Self-Diagnostic Function
8.1 Self-Diagnostic Function
8.1.1 LED Display for Status Condition
Status Indicator LEDs on CPU
Condition
LED status
Description Operation
(Program
RUN PROG. TEST BREAK ERROR BA TT. ALARM
on off off off off off off Normal operation Operation
condition
off on
Varies
off off off off PROG. mode Stop
Flashes
off
Varies
off off off off Forcing on/off in RUN mode Operation
off on on
Varies Varies
off off TEST operation mode (break condition) Stop
on off on off
Varies
off off TEST operation mode (operating
condition)
Operation
Abnormal
condition
off on
Varies Varies
on
Varies
off When a self-diagnostic error occurs
(break condition)
Stop
on off off off on
Varies
off When a self-diagnostic error occurs
(operating condition)
Operation
Varies Varies Varies Varies
on on off When CPU backup battery error occurs Operation
Varies Varies Varies Varies Varies Varies
on When a watchdog timer error occurs Stop
off
Flashes Varies
off
Varies Varies
off When remote I/O slave station waiting
error occurs
Stop
Status Indicator of CPU
The CPU has a self-diagnostic function which identifies errors and stops operation if
necessary.
When an error occurs, the status of the status indicator LEDs on the CPU vary, as shown
in the table above.
Status
indicator
LEDs