Product specifications
INSUM Interface – CI857 Section 5 Maintenance
218 3BSE036351-510 A
INSUM Interface – CI857
Table 37. INSUM CI857 – Fault-Finding 
Fault Possible Cause and Corrective Action
Neither R(un) nor F(ault) LEDs 
are ON
The CI857 board is in the process of being 
restarted or configured. Allow time for this to 
finalize
If the condition persists, and no other unit LED on 
the CEX-Bus is lit:
• Check that a valid HW configuration including 
the CI857 is downloaded to the controller.
• Check the CEX-Bus fuse inside the 
processor unit.
• Initiate a reset signal (INIT) from the 
processor unit.
• Replace the CI857 unit.
F(ault) LED is ON Check all cables and connectors for damage and 
loose or poor connections. Repair as necessary.
R(un) LED is flashing Check that the relevant units are sending data.
Check if the CI857 board is in the process of 
being restarted or configured. If so, allow time for
this to finalize.
If the condition persists:
• Halt the application program and initiate a 
restart.
• Replace the CI857 board.
Tx1 LED is ON (not flashing) The unit is not transmitting data.
• Check the CB for a failure message.
Rx1 LED is ON (not flashing) The unit is not receiving data.
• Check all cables and connections.
 CI857 supports hot swap. 










