Alarm definition

Alarms warn about process conditions that can potentially cause problems. Typically, you set up an alarm to become active when a process value exceeds a defined limit. For example, you can set an alarm for a pump that warns when no fluid pressure is detected.

An alarm is an abnormal condition that requires immediate attention. An operator usually acknowledges an alarm. The System Platform framework handles the real-time reporting of alarms and provides special clients for viewing them.

Application and system objects can detect and generate an alarm. To detect an alarm, a system or application object sets a Boolean Attribute flag to indicate whether the alarm condition of the object is currently true or false.

To report an alarm, the object must contain an alarm feature. The alarm feature makes a reference to the object’s Boolean flag to determine whether the alarm condition is true. It then combines this information with the current alarm mode to determine whether to report a this as an active or inactive alarm state. An alarm feature is dedicated to reporting a single alarm condition’s state. The alarm feature sends alarm notification messages to System Platform alarm and event distributors.

Every alarm notification includes a set of fields containing data that describes the alarm. Some alarm notification data is saved as historical data. The following list describes all fields sent with an alarm notification.

• TagName: The name of the object generating the alarm. Saved as historical data.

• Name: The name of the alarm. Saved as historical data.

• InAlarm: A Boolean value that indicates whether the object’s alarm state is currently active or inactive. Saved as historical data.

• Quality: The current quality of the data upon which the alarm is based. Saved as historical data.

• OnTimeStamp: The time that the attribute value transitioned to an alarm state. The value timestamp of the attribute is used, if available. If not, the timestamp is the AppEngine scan time. Saved as historical data.

• OffTimeStamp: Time that the alarmed attribute value returns to normal. The value timestamp of the attribute is used, if available. If not, the OffTimeStamp is the AppEngine scan time. If an active alarm is disabled, it forces a return to normal and the timestamp is the current time. Saved as historical data.

• Category: An integer between 1 and 14 that identifies the type of alarm and source of the alarm. These values are associated with Internationalized category labels.

  Alarm category labels can be localized to other languages. Application Server uses the default Galaxy language to retrieve these strings and send them to InTouch. The alarm category labels appear in InTouch and InTouch history as the default Galaxy language strings. Saved as historical data.

• Priority: An integer value from 1 to 999 indicating the severity of the alarm. An alarm priority of 1 is most urgent and 999 least urgent.

• TargetValueReference: An optional field that makes a reference to the target value of the alarm. Not saved as historical data.

• ActualValueReference: An optional field that makes a reference to the actual attribute value for the alarm condition. Not saved as historical data.

• TargetValue Snapshot: An optional field containing the target value of the attribute at the time when the alarm became active. Saved as historical data.

• ActualValueSnapshot: An optional field containing the actual value of the attribute at the time when the alarm became active. Saved as historical data.

• EngUnitsReference: The reference to the engineering units string for the condition. Saved as historical data.

• AcknowledgedFlag: Indicates whether the alarm is acknowledged or not. If this flag is FALSE, the alarm is still unacknowledged. Saved as historical event data.

• AcknowledgeTime: Indicates the time when the alarm was acknowledged if the AcknowledgedFlag is TRUE. Saved as historical data at the time of acknowledgement.

• AcknowledgeUserId: The string containing the name of the user who acknowledged the alarm. Saved as historical data at the time of acknowledgement.

• AlarmMode: Indicates if the alarm mode is Enabled, Silenced or Disabled. Saved as historical data at the time when the alarm mode changes.

• Message text describing the alarm, which can be statically or dynamically constructed. The message typically contains the alarm description, the exceeded limit value, and possibly the variable value. For an alarm feature, this message is retrieved by means of a reference to a string/international string attribute in the object. The reference is setup at ObjectDesigner time for alarms. If none is specified, then the common feature short description attribute is utilized. This field is also provided in the alarm feature section and can be dynamically generated and scripted. Saved as historical data.

• Area: The name of the area that contains the object generating the alarm. Saved as historical data.