ABB rec670 - Page 61

Each logical I/O module has an error flag that indicates signal or module failure. The
error flag is also set when the physical I/O module of the correct type is not detected
in the connected slot.
1MRK 511 360-UEN A Section 5
Configuring the IED and changing settings
Bay control REC670 2.1 IEC 55
Commissioning manual