Rockwell Automation FactoryTalk View Site Edition Users Guide - Manual (Page 228)

F ACTORY T ALK V IEW S ITE E DITION U SER ’ S G UIDE
11–16
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 How the system behaves when alarms cross back over trigger thresholds.
 How often the system checks for new alarms.
 Where alarms are logged and printed when redundant HMI servers are in use.
Alarm trigger thresholds
An HMI tag alarm is triggered when the value of an analog tag crosses a specified alarm
threshold.
If the value of the tag fluctuates above and below its alarm threshold, alarms are triggered
each time the tag value rises above or falls below the threshold value. You can specify
whether to use this feature. For an example of how it works, see page 11-4.
Specifying how often the system checks for alarms
The system does not check for alarms more frequently than the maximum update rate
specified in the Alarm Setup editor.
Match the maximum update rate to the rate, at which you expect tag values to change. For
example, if you are monitoring temperatures that fluctuate slowly, check for alarms less
frequently than if you are monitoring manufacturing processes that change rapidly.
Setting up alarm monitoring on redundant servers
If you have set up redundant HMI servers, HMI tag alarms can be logged and printed on
the active HMI server only, or on both the Active and the Standby HMI server.
For more information, see Chapter 14, Setting up FactoryTalk system availability.
Setting up alarm severities
In the Severities tab of the Alarm Setup editor, you can set up logging destinations and
annunciation options for each HMI tag alarm severity and alarm incident.
For each severity or incident, you can log to the alarm log file, to a printer, or to both. You
can also specify how notification is handled, for alarms of particular severities.
For HMI tag alarm states to be synchronized properly, the clocks on the primary and secondary
HMI servers must be kept synchronized to a time server. If the clocks are not synchronized, when
a fail-over occurs, multiple alarms or inconsistent information might display in an alarm summary.