The redundant control system
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3.2.2
System behavior in the event of no synchronization con
-
nection
If the synchronization connection via the SYNC interface is interrupted during runtime, con
-
nection monitoring is performed at Ethernet interface LAN1. The redundant control system
switches to “Basic Sync” redundancy status.
3.2.3
System behavior on switching the PRIMARY controller to
the STOP operating mode
When you switch the PRIMARY controller to the STOP operating mode from
PLCnext Engineer or via the mode selector switch, this will
not
cause the redundancy roles
to be switched over. The PRIMARY controller and the BACKUP controller both switch to the
STOP operating mode.
3.2.4
“FollowUp Sync” redundancy status: Causes
show what causes the redundant control system to switch
to the “FollowUpSync” redundancy status.
3.2.4.1
No redundancy variables in the PLCnext Engineer application
The PLCnext Engineer application does not contain any redundant variables (“Redundant”
check box has not been enabled for any variables).
The PLCnext Engineer application is synchronized between the PRIMARY and BACKUP
controllers; the redundant control system remains in the “FollowUp Sync” state.
3.2.4.2
Configured PROFINET devices cannot be reached
Some of the configured PROFINET devices in the PLCnext Engineer application cannot be
reached.
The PLCnext Engineer application is synchronized between the PRIMARY and BACKUP
controllers; the redundant control system remains in the “FollowUp Sync” state.
3.2.5
“No Sync” redundancy status: Causes
3.2.5.1
No redundancy type
One of the controllers has not been assigned a redundancy type. The controller has the re
-
dundancy type “None”. The redundant control system remains in the “No Sync” state.
3.2.5.2
Duplicate assignment of the redundancy type
Both controllers have been assigned the same redundancy type (“First” or “Second”). The
redundant control system remains in the “No Sync” state.
3.2.5.3
Duplicate assignment of the redundancy role
Both controllers have the same redundancy role (PRIMARY or BACKUP). The redundant
control system remains in the “No Sync” state until the role conflict is automatically resolved.