Rockwell Automation FactoryTalk View Site Edition Users Guide - Manual (Page 234)

F ACTORY T ALK V IEW S ITE E DITION U SER ’ S G UIDE
11–22
• •
•
•
•
About FactoryTalk View SE alarm events
You can customize and extend HMI tag alarm monitoring, by writing alarm-detection
algorithms using PLC ladder logic, custom programs, or other appropriate tools.
You can then add alarm events to the HMI tag alarm subsystem, to respond to the alarm-
detection algorithms for annunciation, logging, printing, and display in alarm summaries.
By using a tag name for an alarm event, you can customize the alarm features of the tag.
For example, you can use alarm events to provide a tag with more than eight thresholds.
You can also use alarm events to specify an alarm’s time stamp.
Since alarms are scanned in the background, alarms that occur rapidly might be shown out
of sequence in FactoryTalk View SE, because they might all be scanned at the same time,
and therefore produce the same time stamp.
If the sequence, in which alarms occur is important, you might want to record accurate
time stamps for HMI tag alarms by buffering the alarms in the PLC, and then using alarm
events to record the alarms with accurate time stamps in FactoryTalk View SE.
To create a FactoryTalk View SE alarm event, use the AlarmEvent command. For details,
see the FactoryTalk View Site Edition Help.
How event-based alarms work
FactoryTalk View SE alarm events let you create alarms without using HMI tags. Event-
based alarms work just like HMI tag alarms. You can:
 Show and filter event-based alarms in HMI tag alarm summaries.
 Acknowledge event-based alarms individually, or with wildcard characters, using the
Acknowledge command.
 Use event-based alarms with alarm system tags.
 Log event-based alarms to disk or printer.
You can also use FactoryTalk View SE alarm events with HMI tag alarm functions in
expressions.
In FactoryTalk View SE, or in alarm-detection algorithms you create for the application,
you can stamp event-based alarms with the current time, or with a specific date and time.
How event-based alarms differ from HMI tag alarms
FactoryTalk View SE alarm events differ from HMI tag alarms in the following ways:
Alarm events are not processed until the AlarmOn command is run, and alarm events are no
longer processed after the AlarmOff command is run.