Can someone explain to me how the SFC module works in a redundant system? I would like to know what happens when a long running process is executing and the master gateway suddenly goes down. Are both the master and the backup gateway in sync at all times? Does this sync happen at defined intervals? Are internal SFC chart properties updated between the two gateways as soon as they are changed? What happens when the master goes down and then comes back up? Does it sync with the backup and then take control of the SFC charts again?
I’m looking into getting this module to do some long run process stuff (maybe 8 hours or so) and I want to know a little more in depth how this is handled for a redundant system. Thanks!
SFCs can be synchronized between a redundant master and backup starting in 7.9.5. You will have to enable redundant synchronization on each individual chart via the Designer. When the master goes down, the backup will start the SFC on the step that was last running on the master.
I have a project that I am working on at the minute which also uses a SFC to control the state of a batch. When I stop the primary gateway the SFC fallsover to the redundant gateway without issue. However when the primary gateway resumes operation the sfc on the primary gateway does not resume where the sfc on the redundant gateway left of.