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12
SLC 500™ Fixed Hardware Style Controllers
Understanding LED Messages
ATTENTION
Identifying Fixed Controller LED Messages
1. Apply power to your controller.
2. Match your controller LEDs with the LEDs located to the left of each table.
3. Move across the table to identify the probable cause.
4. Follow the recommended action steps for each probable cause until the cause is
identified. If recommended actions do not identify the cause, contact your local
Allen-Bradley sales office or distributor.
POWER
PC RUN
CPU FAULT
FORCED I/O
BATTERY LOW
Refer to the following key to determine the status of the LED indicators:
Indicates the LED is off.
Indicates the LED is on.
Indicates the LED is flashing
Publication 1747-IN008B-MU-P
Have all personnel remain clear of the controller and equipment
when power is applied. Have someone ready to operate an
emergency-stop switch in case it becomes necessary to shut off
power to the controller equipment. Also, see NFPA 70E Part II
for additional guidelines for safety related work practices.
Never reach into a machine to actuate a switch since unexpected
machine motion can occur and cause injury.
Probable Cause
Initial CPU Factory
Power-up Condition
Recommended Action
1. Follow the start-up procedures in
the Fixed Hardware style
Controllers Installation and
Operation Manual , Publication
1747-6.21.
2. Download a ladder logic program
to clear the CPU FAULT LED.