Rockwell Automation FactoryTalk Historian SE 3.0 UniInt Interface User Guide - Manual (Page 29)

UniInt Interface User Manual 23
timestamp of the previous value. This is different than the trigger mechanism for output
points. For output points, the timestamp of the trigger value must be greater than (not greater
than or equal to) the timestamp of the previous value.
As of UniInt 3.3.4, conditions can be placed on trigger events. Event conditions are specified
in the extended descriptor as follows:
Event=‘trigger_tag_name’ event_condition
The trigger tag name must be in single quotes. For example,
Event=‘Sinuoid’ Anychange
will trigger on any event to the Historian Tag sinusoid as long as the next event is different
than the last event. The initial event is read from the snapshot. Depending on the interface,
developer-specific event conditions may be configurable. The tag name must be surrounded
by the single quote and there can be no text between the second or closing single quote and
the trigger keyword.
The keywords in the following table can be used to specify trigger conditions.
Event
Condition Description
Anychange Trigger on any change as long as the value of the current event is different than
the value of the previous event. System digital states also trigger events. For
example, an event will be triggered on a value change from 0 to “Bad Input,” and
an event will be triggered on a value change from “Bad Input” to 0.
Increment Trigger on any increase in value. System digital states do not trigger events. For
example, an event will be triggered on a value change from 0 to 1, but an event
will not be triggered on a value change from “Pt Created” to 0. Likewise, an event
will not be triggered on a value change from 0 to “Bad Input.”
Decrement Trigger on any decrease in value. System digital states do not trigger events. For
example, an event will be triggered on a value change from 1 to 0, but an event
will not be triggered on a value change from “Pt Created” to 0. Likewise, an event
will not
be triggered on a value change from 0 to “Bad Input.”
Nonzero Trigger on any non-zero value. Events are not triggered when a system digital
state is written to the trigger tag. For example, an event is triggered on a value
change from “Pt Created” to 1, but an is not triggered on a value change from 1 to
“bad input.”
Unsolicited Inputs
Some interfaces do not poll for data. Rather, the foreign device (Distributed Control System,
PLC, SCADA, etc.) is in control of what type of data is sent to the interface and when it is
sent. For unsolicited data input, the value of Location4 is meaningless to UniInt. The
interface may make use of Location4 for some other Historian tag configuration value.
Please see the interface documentation for a description of how Location4 is used for
unsolicited input tags.
Output Points
Output points control the flow of data from the Historian Data Archive to any destination
that is external to the Historian Data Archive, such as a PLC or a third-party database. For