Table C.1lists EEMUA terms and how OPC UA terms maps to them.
EEMUA Term |
OPC UA Term |
EEMUA Definition |
Accepted |
Acknowledged=True |
An Alarmis accepted when the Operatorhas indicated awareness of its presence. In OPC UA this can be accomplished with the Acknowledge Method. |
Active Alarm |
Active = True |
An Alarm Conditionwhich is on (i.e. limit has been exceeded and Conditioncontinues to exist). |
Alarm Message |
Message Property (defined in OPC 10000-5.) |
Test information presented to the Operatorthat describes the Alarm Condition. |
Alarm Priority |
Severity Property (defined in OPC 10000-5.) |
The ranking of Alarmsby severity and response time. |
Alert |
- |
A lower priority Notificationthan an Alarmthat has no serious consequence if ignored or missed. In some Industries also referred to as a Prompt or Warning”. No direct mapping! In UA the concept of Alertscan be accomplished by the use of severity. E.g., Alarmsthat have a severity below 50 may be considered as Alerts. |
Cleared |
Active = False |
An Alarm state that indicates the Conditionhas returned to normal. |
Disable |
Enabled = False |
An Alarmis disabled when the system is configured such that the Alarmwill not be generated even though the base Alarm Conditionis present. |
Prompt |
Dialog |
A request from the control system that the Operatorperform some process action that the system cannot perform or that requires Operatorauthority to perform. |
Raised |
Active = True |
An Alarmis Raisedor initiated when the Conditioncreating the Alarmhas occurred. |
Release |
OneShotShelving |
A ‘release’ is a facility that can be applied to a standing (UA = active) Alarmin a similar way to which Shelvingis applied. A released Alarmis temporarily removed from the Alarmlist and put on the shelf. There is no indication to the Operatorwhen the Alarmclears, but it is taken off the shelf. Hence, when the Alarmis raised again it appears on the Alarmlist in the normal way. |
Reset |
Retain=False |
An Alarmis Reset when it is in a state that can be removed from the Display list. OPC UA includes Retainflag which as part of its definition states: “when a Clientreceives an Eventwith the Retainflag set to False, the Clientshould consider this as a Condition/Branch that is no longer of interest, in the case of a “current Alarmdisplay” the Condition/Branch would be removed from the display” |
Shelving |
Shelving |
Shelvingis a facility where the Operatoris able to temporarily prevent an Alarmfrom being displayed to the Operatorwhen it is causing the Operatora nuisance. A Shelved Alarmwill be removed from the list and will not re-annunciate until un-shelved. |
Standing |
Active = True |
An Alarmis Standingwhilst the Conditionpersists (Raisedand Standingare often used interchangeably)’. |
Suppress |
Suppress |
An Alarmis suppressed when logical criteria are applied to determine that the Alarmshould not occur, even though the base Alarm Condition(e.g. Alarmsetting exceeded) is present. |
Unaccepted |
Acknowledged = False |
An Alarmis accepted when the Operatorhas indicated awareness of its presence. It is unaccepted until this has been done. |
|
|
|