Rockwell Automation 1791-IOBB USER MANUAL - Manual (Page 29)

Troubleshooting
Chapter 5
5Ć2
Table 5.A
Troubleshooting Chart
Indication Probable Cause Corrective Action
Green COMM LED on
Red POWER LED on
I/O status LED on/off
Normal indication None required
Red POWER LED flashing Block failed self-test, or a major fault is detected.
Cycle power to the block. If problem persists,
replace the block.
Red POWER LED off No 24V dc power connected, or hardware fault. Check 24V dc power to block
Green COMM LED off No communication with processor, scanner etc.
Check that power LED is on. Make sure that
proper number of blocks are configured.
Check remote I/O link or distributed I/O link wiring.
Green COMM LED flashing
Reset command (or output disable bit for SLC) has
been issued by processor or scanner.
Check program. Correct as necessary.
Green COMM LED flashing
SLC or programmable controller not in run mode. Place in run mode.