HI,
nas is a synchronous process.
each alarm must be compared to every AO to see if it matches.
each AO has an order by number that can be set.
If in the NAS AO screen you scroll to the right you will see this order.
This is the order that will be processed.
A couple of things I usually suggest.
1) do not have too many AO set for on arrival. Set most to on overdue at least 5s.
2) if an alarm will not need to be evaluated by any other AO have the AO break and not check other AO.
3) do not use on interval as this requires nas to go through ALL open alarms again on every interval.
hope this helps