Rockwell Automation FactoryTalk View Site Edition Users Guide - Manual (Page 235)

11 • S ETTING UP HMI TAG ALARMS
11–23
•
•
•
• •
11
•
Pla
ceho
lde
r
 You cannot specify thresholds for analog alarm events. All analog alarm events have a
value of zero.
 You cannot specify alarm labels for event-based alarms. That is, you cannot use the
IntoAlarm and OutOfAlarm labels for HMI digital tag alarms, or the threshold labels
for HMI analog tag alarms.
 You cannot suppress event-based alarms.
 Alarm events have no acknowledge and handshake bits.
 You cannot use the Identify feature with event-based alarms, to run a command,
macro, or custom program.
 Event-based alarms are not retained after the AlarmOff command is run, or after the
HMI server shuts down.
Naming alarm events
You must provide a name for each alarm event you create. The event name can be a tag in
the HMI server’s tag database, as long as the tag has no alarm conditions set up for it.
Alarm event names can be up to 255 characters long and can contain the following
characters:
 A to Z
 0 to 9
 underscore ( _ ) and dash (–)
When an alarm event name starts with a number or contains a dash, enclose the name in
brackets { } when you use it in an expression, for example, {N33-0}.
Also use brackets when using wildcard characters to represent multiple alarm events in an
expression, for example, {alarm*}.
Alarm event names preserve upper and lower case for readability but are not case
sensitive. For example, the alarm event name HopperOverflow is the same as
hopperoverflow.
How event-based alarms are logged
The alarm log file shows event-based alarms in the order, in which the alarm transactions
were logged. If you specify a time stamp for alarm events, the alarm log could show the
transactions out of order.