AC400 system alarms
system alarms coming from an AC450 controller become active and inactive at the same moment in 800xA 6.0, even though the failure persists. As a result, an alarm disappears from the system alarm list after acknowledgment. On the other hand, system alarms related to 800xA or AC800M controllers remain acknowledged in the system alarm list as long as the alarm condition is active. Is it possible to have the same behaviour for AC400 system alarms?
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Due to the nature of Advant Controller 400 system messages, these "alarms" are in fact stateless events distributed on MB300 to all members of the Master View Table.
In 800xA there is a feature called System Alarms with which you can convert stateless events into alarms (still stateless).
The conversion of stateless event into alarm comes with a drawback, the alarm is either "Inactive on creation" *OR* "Inactive on acknowledge"
E.g. if you look at the more simple MB300 "node down" and "node up" messages seen in RTA Board Maintenance and OnLine Builder, they become stateless alarms that "evaporates" on acknowledge, even though the state (node down) is still present. The "node up" is equally strange, why "alarm" on something positive...
This all boils down to the stateless delivery of AC400 system events to RTA and HMI and the drawbacks of converting them into alarms.
There has not been a business case (or even a possibility) to have the MB300 OPC AE server to collect and remember these states up to date. Please speak with your regional ABB sales representative about future enhancements.