Method for redundant controller synchronization for bump-less failover during normal and program mismatch conditions

Abstract

The present invention relates generally to process control systems and devices and, more particularly, to an apparatus for and a method of implementing redundant controller synchronization for bump-less failover during normal and mismatch conditions at the redundant controllers. The redundant controllers are configured to transmit state information of the process control areas of the primary controller to the backup controller that is necessary for synchronizing the redundant controllers but is not typically transmitted to other devices during the performance of process control functions. Synchronization messages are transmitted from the primary controller to the backup controller each time one of the control areas executes to perform process control functions. In other aspects, the redundant controllers are configured to determine state information at the backup controller from other process control network information during a failover of the primary controller where a mismatch condition exists between the control areas of the two controllers during the downloading of reconfigurations, and to initialize the backup controller at startup when the mismatch condition exists.