For the purposes of this document, the terms and definitions given in OPC 10000-1, OPC 10000-3, OPC 10000-4, and OPC 10000-5as well as the following apply.

Operatoraction that indicates recognition of an Alarm

Note 1to entry: This definition is copied from EEMUA. The term “Accept” is another common term used to describe Acknowledge. They can be used interchangeably. This document will use Acknowledge.

state for an Alarmthat indicates that the situation the Alarmis representing currently exists

Note 1to entry: Other common terms defined by EEMUAare “Standing” for an Active Alarmand “Cleared” when the Conditionhas returned to normal and is no longer Active.

Alarmfor which the set point or limits are changed by an algorithm.

Note 1to entry:  AdaptiveAlarmsare alarms that are adjusted automatically by algorithms. These algorithms might detect conditions in a plant and change setpoints or limits to keep alarms from occurring. These changes occur, in many cases, without Operatorinteractions.

condition during which the alarm rate is greater than the Operatorcan effectively manage

Note 1to entry:  OPC UA does not define the conditions that would be considered alarm flooding, these conditions are defined in other specification such as IEC 62682or ISA 18.2

group of Alarmsthat is used to suppress other Alarms.

Note 1to entry:  An AlarmSuppressionGroupis an instance of an AlarmGroupTypethat is used to suppress other Alarms. If any Alarmin the group is active, then the AlarmSuppressionGroupis active. If all Alarmsin the AlarmSuppressionGroupare inactive then the AlarmSuppressionGroupis inactive

Note 2 to entry: The Alarmto be affected references AlarmSuppressionGroupswith a HasAlarmSuppressionGroup ReferenceType.

Conditiongrouping that indicates in which domain or for what purpose a certain Conditionis used

Note 1to entry: Some top-level ConditionClassesare defined in this specification. Vendors or organisations may derive more concrete classes or define different top-level classes.

specific state of a Condition

Note 1to entry: The Servercan maintain ConditionBranchesfor the current state as well as for previous states.

element which a specific Conditionis based upon or related to

Note 1to entry: Typically, it will be a Variablerepresenting a process tag (e.g. FIC101) or an Objectrepresenting a device or subsystem.

In Events generated for Conditions, the SourceNode Property (inherited from the BaseEventType) will contain the NodeId of the ConditionSource.

Operatoraction informing the Serverthat a corrective action has been taken to address the cause of the Alarm

system is configured such that the Alarmwill not be generated even though the base Alarm Conditionis present

Note 1to entry:  This definition is copied from EEMUAand is further defined in EEMUA.

In IEC62682 disable is referenced as “Out of Service”.

alarm that remains in alarm state after the process condition has returned to normal and requires an Operatorreset before the alarm returns to normal

Note 1to entry: Latching alarms are typically discrepancy alarms, where an action does not occur within a specific time. Once the action occurs the alarm stays active until it is reset.

special user who is assigned to monitor and control a portion of a process

Note 1to entry: “A Member of the operations team who is assigned to monitor and control a portion of the process and is working at the control system’s Console” as defined in EEMUA. In this standard an Operator is a special user. All descriptions that apply to general users also apply to Operators.

act of providing an update to an Event Subscriptionthat provides all Alarmswhich are considered to be Retained

Note 1to entry: This concept is further defined in EEMUA.

Alarmin a state that is interesting for a Clientwishing to synchronize its state of Conditions with the Server’s state

facility where the Operatoris able to temporarily prevent an Alarmfrom being displayed to the Operatorwhen it is causing the Operatora nuisance

Note 1to entry ”A Shelved Alarmwill be removed from the list and will not re-annunciate until un-shelved.” as defined in EEMUA.

act of determining whether an Alarmshould not occur

Note 1 to entry: “An Alarm is suppressed when logical criteria are applied to determine that the Alarm should not occur, even though the base Alarm Condition (e.g. Alarm setting exceeded) is present” as defined in EEMUA. In IEC62682 Suppressed Alarms are also described as being “Suppressed by Design”, in that the system is designed with logic to Suppress an Alarm when certain criteria exist. For example, if a process unit is taken off line then low level alarms are Suppressed for all equipment in the off-line unit.