Rockwell Automation 1756-DH485 ControlLogix DH-485 Communication Module User Manual - Manual (Page 99)

Publication 1756-UM532A-EN-P - May 2006
Troubleshoot the 1756-DH485 Module B-3
Interpret the Alphanumeric
Indicators Your 1756-DH485 module displays alphanumeric codes that provide
diagnostic information about your module. The alphanumeric display flashes
the codes at approximately one-second intervals. This table summarizes the
codes.
Alphanumeric Display Descriptions
Message Description Recommended Action
ONLY NODE Only node on
DH-485 link. Check the cables.
OFF LINE DH-485 link is in STOP
state. Correct the configuration.
DUPL NODE DH-485 Duplicate
node address. Choose another node address.
ONLY NODE Only node on
DH-485 link. Check the cables.
OFF_LINE Not trying to
communicate. None. Normal state if controller is not
controlling remote I/O.
OK Normal operation. None.