The first section of the application (section 0) is executed by both Primary and Standby Processors. It means that in the stand by PLC you can execute program in first section without any link with the primary.
Variables which are not exchanged in every cycle with the primary need to be defined in the non transfer area, for example %MW0 to %MW99
Variables which are not exchanged in every cycle with the primary need to be defined in the non transfer area, for example %MW0 to %MW99