GFK-1527A Chapter 5 Fault Detection 5-3
5
PLC Fault Table Messages for Redundancy

The following table lists messages, descriptions, and corrective actions for error codes associated

with the redundancy fault group. These error codes can be viewed by selecting Ctrl-F on the

corresponding redundancy fault (in Logicmaster 90-70) or double-click on the corresponding fault

(in Control). The entire fault d at a (including these error codes) can a lso be accessed with a

SVC_REQ and other applications that communicate with the CPU.

Error
Code Message Fault Description Corrective Action
1 Primary Unit is Active and
Secondary Unit is Backup. The primary and secondary units have
switched roles. None required.
2 Secondary Unit is Active
and Primary Unit is
Backup.
The secondary and primary units have
switched roles. None required.
3 Primary Unit is Active; No
Backup Unit Available. The primary unit has transitioned to RUN
mode and is running as a stand-alone unit. Secondary unit MUST be placed in RUN
mode with a comparable configuration in
order to have a synchr on i zed system.
4 Secondary Unit is Active;
No Backup Unit Available. The secondary unit has transitioned to RUN
mode and is running as a stand-alone unit. Primary unit MUST be placed in RUN
mode with a comparable configuration in
order to have a synchr on i zed system.
5 Primary Unit Has Failed;
Secondary Unit is Active
w/o Backup.
Primary unit has recorded a fatal fault, has
been powered down, or has lost ability to
communicate with the secondary unit while
acting as the active or backup unit.
Secondary unit will continue running as a
stand-alone unit.
If primary unit has a l s o logged the fault
“Secondary Unit Has Failed: Primary Unit
is Active w/o Backup”, then
communications has been broken between
the two units and must be repaired. If a
fatal fault has bee n l ogge d in the primary
unit, the indicated fault must be repaired.
Power may have to be cycl e d on one of the
units in order to re-e stablish
communications and return to a
synchronized system.
6 Secondary Unit Has Failed;
Primary Unit is Active w/o
Backup.
Secondary unit has recorded a fatal fault, has
been powered down, or has lost ability to
communicate with the primary unit while
acting as the active or backup unit. The
primary unit will continue running as a
stand-alone unit.
If secondary unit h as also logged the fault
“Primary Unit Has Failed: Secondary Unit
is Active w/o Backup”, then
communications has been broken between
the two units and must be repaired. If a
fatal fault has bee n l ogge d in the secondary
unit, the indicated fault must be repaired.
Power may have to be cycl e d on one of the
units in order to re-e stablish
communications and return to a
synchronized system.
7 Synchronization Failure;
Both Units are Active. A communications failure between the two
units has caused each unit to become stand-
alone units. Communications has since been
restored.
One of the units should be power cycled to
return to a synchronized system. NOTE:
The Genius blocks wil l respond to the unit
that is using Serial Bu s Address 31.
8 Unable to Switch
Redundancy Roles An attempt to switch redundancy roles was
made when it was not possible to perform
the switch.
None required.