Omron CS1D DUPLEX SYSTEM - 10-2009 Operation Manual page 457

Troubleshooting Errors in Duplex Connecting Cables
Cause
Cable IN/OUT connections are
reversed.
Faulty Expansion Unit
Remedy
Connect the Connecting Cables properly.
If either cable is connected to the wrong side
when the power supply is turned ON, an I/O bus
error C will occur and the PLC will not operate.
Note If the cable to the other slot is discon-
nected, the PLC will stop.
Replace the Expansion Unit. Refer to 11-6
Replacement of Expansion Units for details.
Note If the cable to the other slot is discon-
nected, the PLC will stop.
Section 10-4
421