Scheduler redundancy can be illustrated by using the diagram and the table below.

In this example, PC1 is the Primary Scheduler while PC2 is the standby Scheduler. Both PC3 and PC4 have the same copy of the Scheduler configuration. PC3’s copy is used first before PC4s.

It should be noted that the Scheduler under CitectSCADA needs a Client and Alarm Server to be on the same PC. They can either be in the same CitectSCADA process or in separate processes on the same PC.

Standby use – Activation  of the standby scheduler will be automatic, as long as the system has been setup correctly.  Regardless of the status of the current schedule, the Standby will execute the next sequence in the schedule.

If the Scheduler process dies then there is NO automatic switchover to the other Scheduler.
If PC3 goes down, then the Scheduler will switch to the configuration data on PC4. There is no automatic switch back should PC3 become available again.