User manual

Troubleshooting
Scanner Mode 5-16
Classic PLC-5
processors only
Troubleshooting – Classic PLC-5 Processors (except PLC-5/10 and PLC-5/12) in Scanner Mode
Indicator Color Description Probable Cause Recommended Action
COMM green
(blinking rapidly or
slowly)
processor is transmitting or receiving on
DH+ link
normal operation none
red
(steady)
watchdog time-out hardware error Turn power off, then on.
Check that the software
configurations match the
hardware set-up. Replace
the processor.
red
(sporadic)
bad communication on DH+ link duplicate station address
selected
Correct station address
off • if directly connected to processor, no
communication on DH+ link
• if last processor on DH+ link, no
communication on DH+ link
• no action required
• Check DH+ wiring
connections.
COMM
BATT
FAULT
REM I/O PROC
ACTIVE
RUN
ADPT FORCE
REM
R
U
N
P
R
O
G