System and method for periodic task resumption following redundant control system switchover

In a redundant industrial control system, a method for ensuring timely execution of periodic tasks, comprising:

• receiving a wakeup time array having at least one wakeup time element corresponding to a periodic task and a current time value from a primary control module;
• and
• scheduling a run time for the periodic task at switchover based on the wakeup time element corresponding to a periodic task and the current time value from the primary control module.

In a redundant control system having a primary controller for controlling a process and a secondary controller adapted to assume control of the process upon a switchover event, a method for operating the primary controller, comprising:

• sending wakeup time information to the secondary controller during qualification of the secondary controller, wherein the wakeup time information comprises at least one wakeup time value corresponding to at least one periodic task associated with the process.

In a redundant control system having a primary controller for controlling a process and a secondary controller adapted to assume control of the process upon a switchover event, a method for operating the secondary controller, comprising:

• obtaining wakeup time information from the primary controller during qualification of the secondary controller, wherein the wakeup time information comprises at least one wakeup time value corresponding to at least one periodic task associated with the process;
• and
• running the at least one periodic task according to the wakeup time information from the primary controller after a switchover event.

A primary controller for controlling a process in a redundant control system having a secondary controller adapted to assume control of the process upon a switchover event, and to send wakeup time information to the secondary controller during qualification of the secondary controller, wherein the wakeup time information comprises at least one wakeup time value corresponding to at least one periodic task associated with the process.

A secondary controller adapted to assume control of a process from a primary controller in a redundant control system upon a switchover event, and to obtain wakeup time information from the primary controller during qualification of the secondary controller, wherein the wakeup time information comprises at least one wakeup time value corresponding to at least one periodic task associated with the process;

• wherein the secondary controller is further adapted to run the at least one periodic task according to the wakeup time information from the primary controller after a switchover event.