User manual

Troubleshooting
Remote I/O 5-17
Classic PLC-5
processors only
Troubleshooting – Remote I/O System, 1771-ASB series C and series D
See page 5-20 for footnotes
Indicators
Active Adapter
Fault
I/O
Rack
Description Probable Cause Recommended Action
On Off Off normal indication; remote adapter is fully
operational
Off On Off RAM memory fault
watchdog time-out
Replace module
On Blink Off module placement error I/O module in incorrect
slot
Place module in correct slot in chassis
Blink in unison Off incorrect starting I/O group number error in starting I/O
group number or I/O
rack address
Check switch settings. Refer to table 3.B to
verify acceptable beginning I/O group number;
set switches correctly.
On On On module not communicating incorrect baud rate
setting
Check switch settings
Off On On module not communicating scan switch set for “all
but last 4 slots” in 1/4
rack
Reset scan switch setting
ACTIVE
ADAPTER
FAULT
I/O RACK
FAULT