Controller Communication Channel Troubleshooting - Allen-Bradley PLC-5 User Manual

F-4 Troubleshooting
Indicator Color
A or B Green
(steady)
Green
(blinking
rapidly or
slowly)
Red
(steady)
Red
(blinking
rapidly or
slowly)
Off
Publication 1785-UM012D-EN-P - July 2005

Controller Communication Channel Troubleshooting

Channel Mode Description
Remote I/O Scanner Active Remote I/O link, all
adapter modules are
present and not faulted
Remote I/O Adapter Communicating with
scanner
DH+ Controller is transmitting or
receiving on DH+ link
Remote I/O Scanner At least one adapter is
faulted or has failed
DH+ No other nodes on network
Remote I/O Scanner Hardware fault
Remote I/O Adapter
DH+
Remote I/O Scanner All adapters faulted
DH+ Bad communication on DH+ Duplicate
Remote I/O Scanner Channel offline
Remote I/O Adapter
DH+
Probable Cause Recommended Action
Normal operation No action required
• Power off at • Restore power to
remote rack the rack
• Cable broken • Repair cable
Hardware error Turn power off, then on
Check that the software
configurations match the
hardware set-up
Replace the controller.
• Cable not • Repair cable
connected or
broken
• Power off at • Restore power to racks
remote racks
Correct station address
node detected
Channel is not Place channel online
being used if needed