Rockwell Automation FactoryTalk View Site Edition Users Guide - Manual (Page 561)

20 • C REATING EXPRESSIONS
20–15
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20
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Pla
ceho
lde
r
Returns 1 (true) when the first time the expression is evaluated after 2:30 p.m. on Sunday,
August 21, 2005.
BEFORE_TIME(“aug 21 2005”)
Returns 1 (true) the first time the expression is evaluated before August 21, 2005.
INTERVAL(“1 min”)
Returns 1 (true) if a minute has elapsed since the expression last returned a 1.
(tag1>500) and INTERVAL (“30 sec”)
Returns 1 (true) when tag1>500 on some 30-second interval since the event file started
running. (It does not mean 30 seconds after tag1>500.)
Tag functions
Use the built-in tag functions to examine the status of a tag, HMI tag alarm, or HMI alarm
event (or multiple tags, or alarm events).
For information about setting up HMI tag alarms, see Chapter 11, Setting up HMI tag
alarms.
If a graphic display requires more than 20 HMI tag alarm functions, it is recommended that
you use the alarm functions in derived tags. For details, see the FactoryTalk View Site Edition
Help.
This function Returns this value
alm_ack(tag or alarm event)
or
alm_ack(tag*)
1 (true) if the tag’s alarm or the alarm event has
been acknowledged.
If examining multiple tags, 1 (true) if one or more
alarms have been acknowledged.
alm_allacked(tag or alarm event)
or
alm_allacked(tag*)
1 (true) if the tag’s alarm or the alarm event has
been acknowledged.
If examining multiple tags, 1 (true) if all tags
matching the pattern have been acknowledged. If
any of the tags has not been acknowledged, the
expression returns 0.
alm_fault(tag or alarm event)
or
alm_fault(tag*)
1 (true) if there has been an alarm fault for the
specified tag or alarm event.
If examining multiple tags, 1 (true) if there has
been an alarm fault for one or more of the tags.