Alarm not getting ackowledge for a particular controller in 800xA4.1 system
We have about 4sets of redundant controllers in a system. for one controller alarms are not getting acknowledged.
Earlier controller ans servers time is not in sync, 2days back we done time sync, still problem persists.
Can any one suggest the solution or workaround?
Answers
Hi
right click on faceplate and see if you get acknowledge option in this list if not then restart your alarm manager in the service structure. Normal alarm acknowledge have problem due to alarm manager
Source: Alarm Acknowledge issue
Proper time synchronization is of essence when it comes to alarm and event.
We need to establish if the discrepancy is in the controller, OPC AE server or 800xA alarm manager service.
What does alarm list for the objects in concern show?
What state is the alarm in?
Can you connect a 3rd party OPC AE client directly to the AC800 OPC server perform a "Refresh" and see what state the alarm is in? If you have redundant connectivities, begin with the CS where the event collector service provider in concern is in "service" state.
/Stefan
Thanks Stefan,
The Alarm acknowledge is resolved i guess, it's under observation.
The things we have done is
Alarm State wasin ABL--Auto disable
1.We restarted the alarm manager and when we tried to acknowledge it was not getting acknowledge then we enabled and disable the object from the faceplate then it got acknowledge. We repeated the same procedure to acknowledge all the alarms in the list.
2. We generated few alarms and tried to acknowledge now it is working but later we observed that alarms are generating and able to acknowledge but same was not recording in the Event List.
Let me know if you need more assistance.
In theory, this is what happens when an alarm comes, is acknowledged and goes:
0. Alarm is triggered. Controller send information via MMS to OPC server
1. Alarm is going from inactive/acknowledged -> active/unacknowledged state.
ActiveTime, SourceName, Condition and cookie (a serial number) is generated and sent to the HMI which in turn creates a new alarm.
2. Acknowledge order is submitted from HMI to OPC server
ActiveTime, SourceName, Condition and cookie (a serial number) is supplied as keys.
3. If the keys in step 2 matches, the OPC server returns S_OK otherwise a failure code is returned and HMI generates a "Failed to acknowledge alarm condition ..." system alarm.
4. The acknowledge order is forwarded down to controller via MMS
5. Acknowledgment is made in controller
6. Controller issues a active, acknowledged event via MMS to OPC server
7. OPC server forwards the active/acknowledged event to HMI
ActiveTime, SourceName, Condition and cookie (a serial number) is supplied as keys. The alarm stops blinking.
8. Alarm trigger is cleared, alarm returns to idle. Controller sends inactive/acknowledged to OPC server via MMS.
9. OPC server forwards the inactive/acknowledged event to HMI
ActiveTime, SourceName, Condition and cookie (a serial number) is supplied as keys.
10. Alarm is removed from alarm list.
ABL, Auto-disable happens when the alarm goes to the inactive, unacknowledged state for the third time without being acknowledged.
What could have happened then?
Alarm Manager can only hold 10.000 alarms and if the "Make new alarm each time a condition gets active" is enabled it may quickly run out of storage forcing the oldest alarm to be removed from the lists. In theory, acknowledging the most recent alarm should result in that older alarms in inactive, unacknowledged state are acknowledged as well, but it might not work in practice. Its recommended to have the "Make new..." setting disabled to limit each object/alarm/condition to only one seat out of the 10.000 available.
Another theory might be that application download was made to AC800, but "Refresh" is not performed as expected (maybe from misconfiguration of event collector ["Supports refresh" setting must be enabled] or other mishap). Alarm content differs between OPC server and HMI. Acknowledge will fail if key values are not matching.
By connecting a 3rd party OPC AE client directly to the OPC AE server in regard it might be possible to detect if OPC server content differs from HMI content.
/Stefan
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