Defines when emergency operation can be activated. Not relevant for DFT mode "Parallel operation only".
Example
Select 0: Burner in operation
Both burners are starting but are still in the purge phase. A safety shut-off occurs on burner 1 during purging.
In this case, emergency operation is not activated due to the selection 0: Burner in operation, since the two burners have not yet reached the "in operation" status.