Rockwell Automation 1747-DSN DISTRIBUTED I/O SCANNER - Manual (Page 37)

SCANNER
COMM FAULT
Chapter 4
Operation and Troubleshooting
4–7
When the scanner’s LEDs change state, use the following table to isolate the
cause.
LED
Condition
Problem Solution
FAULT LED
flashing red Configured for an invalid
number of I/O blocks. Modify DIO initialization rung in SLC
program to reflect the correct number
of I/O blocks.
FAULT LED
solid red Duplicate scanner detected,
or hardware error on scanner. Disconnect DIO Link from scanner and
cycle scanner power. If the FAULT
LED is off, look for another scanner on
the network. If the condition persists,
replace the scanner.
COMM LED
off Configuration Data Valid bit
not set in output image
control word (O:e.0). Add a rung to the SLC program that
sets the Configuration Data Valid bit
after communications is established.
COMM LED
flashing green An I/O block is not properly
configured, connected,
powered, or is faulted. Find the I/O block with the COMM LED
off. Check the DIO Link connections,
power, and switch settings.
COMM LED
flashing red Scanner is incorrectly
connected, or all I/O blocks
are incorrectly configured,
have no power, or are faulted. Check DIO Link wiring at scanner.
Check I/O block configuration and
power status.
COMM LED
solid red Duplicate scanner detected,
or hardware error on scanner. Disconnect DIO Link from scanner and
cycle scanner power. If the FAULT
LED is off, look for another scanner on
the network. If the condition persists,
replace the scanner.
Troubleshooting