How to
Configuring an Out of Reference Range Alarm
You configure the properties of a out of reference range alarm to meet the unique needs of your site.
The out of reference range alarm monitors variable movements comparing to a reference variable. By setting an upper deviation limit and lower deviation limit, you configure the tolerance the monitored variable can vary from the reference variable before the alarm is triggered. The upper alarm limit of the monitored variable is equal to the reference point current value plus the upper deviation limit. The lower alarm limit of the monitored variable is equal to the reference point current value minus the lower deviation limit.
An out of range alarm with upper deviation limit, lower deviation limit, and deadband set to zero must meticulously follow the reference variable to not trigger the alarm.
Out of reference alarm triggers an alarm when the monitored variable goes outside the upper or lower deviation limit of the reference variable.
For example, you have a reference variable that is designed to follow the optimal room temperature in a office. By connecting the reference variable and the variable from a thermistor, placed in the office, to an out of reference range alarm, you can set up the alarm to trigger when the temperature differs more than 5 °C (41°F) from the reference variable.
You can configure out of reference range alarms using shunt variable, time delay, and deadband. For more information, see Alarm Functions .
In WorkStation, in the System Tree pane, select the out of reference range alarm you want to configure.
On the File menu, click Properties .
Edit the basic settings:
Table: Basic Settings Page or Tab
Property
Description
Type
Displays the alarm type of the alarm.
Name
Displays the name of the alarm.
Description
Type to change the description of the alarm.
Edit the alarm trigger properties:
Table: Alarm Trigger Page or Tab
Property
Description
Upper limit
Enter the highest value the monitored variable can increase to before the alarm is triggered.
Lower limit
Enter the lowest value the monitored variable can decrease to before the alarm is triggered.
Deadband
Enter the range the monitored variable has to pass within the normal range before the alarm is reset.
Monitored variable
Enter the path to the variable that is monitored by the alarm.
Reference variable
Enter the reference variable that is compared with the monitored variable.
Disable alarm
Select to disable the alarm, for example, before deployment.
Alarm state
Displays the present state of the alarm. For more information, see Alarm States .
Disabled cause
Displays the cause for the alarm being disabled:
Shunt variable means that the alarm has been disabled by a shunt variable
User means that the alarm has been disabled by the user
System means that the alarm has been disabled by the system
Alarm delay (s)
Enter the time, in seconds, the alarm has to be within the alarm criteria before the alarm is triggered.
Reset delay (s)
Enter the time, in seconds, the alarm has to be within the reset criteria before the alarm state is changed from alarm to reset.
Shunt variable 1
Enter the shunt variable that is used to enable or disable the alarm. For more information, see Shunt Variables .
Invert
Select to invert the shunt value, that is, enable the alarm when the shunt value is active and disable the alarm when the shunt value is inactive. For more information, see Shunt Variables .
Operator
Select AND or OR to add logic between the first and the second shunt variable. For more information, see Shunt Variables .
Shunt variable 2
Enter the second shunt variable that is used to enable or disable the alarm. For more information, see Shunt Variables .
Invert
Select to invert the shunt value, that is, enable the alarm when the shunt value is active and disable the alarm when the shunt value is inactive. For more information, see Shunt Variables .
Edit the presentation properties:
Table: Presentation Page or Tab
Property
Description
Above upper limit message
Type the message to display when the variable exceeds the upper limit of the alarm.
Below lower limit message
Type the message to display when the variable falls below the lower limit.
Reset message
Type the message to display when the alarm is reset.
Category
Enter the category the alarm belongs to.
Prefix for alarm source name
Type a prefix that is added to the beginning of the source name property of an alarm record.
Above upper limit priority
Enter the priority level of the alarm when the variable exceeds the upper limit.
Below lower limit priority
Enter the priority level of the alarm when the variable falls below the lower limit.
Reset priority
Enter the priority level of the alarm when it is reset.
Same priority
Select to set all priorities to the same value.
Auto hide
Select to automatically hide the alarm in the Alarms pane or Alarm View.
Flashing alert
Select to make the alarm row flash in the Alarms pane and Alarm Views when the alarm is triggered.
Audible alert
Select to make the alert audible when the alarm is triggered.
Disable state-change logging
Select to prevent an alarm state change from creating an event.
Edit the user action properties:
Table: User Action Page or Tab
Property
Description
Acknowledgement type
Select the type of acknowledgement for the alarm.
Cause note group
Enter the cause note group that is used by the alarm.
Action note group
Enter the action note group that is used by the alarm.
Checklist
Enter the checklist that belongs to the alarm.
Required User Actions
Select what actions the user has to perform when any of the listed events occur.
Edit the attachment properties:
Table: Attachment Page or Tab
Property
Description
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Add attachment
Click to add an attachment to the alarm. For more information, see Alarm Attachments .
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Remove attachment
Click to remove an attachment.
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Navigate to
Click to open the attachment that is selected in the attachment list.
Display on alarm
Select to display the attachment when the alarm is going from Normal to Alarm state.
Click OK .
Out of Reference Range Alarms
Alarm Functions
Alarm States
Shunt Variables
Priority
User Actions
Alarm Attachments