168 • SMP Gateway User Manual
17.1.3 Understanding Automation Functions Settings
Complete documentation on the automation functions is available in the Application Notes folder
of the SMP Gateway Software & Tools CD-ROM, in a document called SMP Automation
Functions.
17.1.4 Using the Logic Processor
SMP Config enables you to derive a data point through a mathematical expression that includes
existing data points.
For instance, you may want to export the value of a certain power aspect such as phase imbalance
but no such data point is available. If data points are available for voltage and current, you can
simply define three new data points calculated as the voltage times the current for each phase, then
check power imbalance between the three points.
The expression for deriving a calculated data point can be evaluated in one of two ways:
By exception.
Whenever there is a transition on the data points included in the expression. If you choose this
option, you also specify whether the evaluation is to be triggered by a specific data point or by
any data point in the expression.
Periodically.
Every X milliseconds.
You can choose to have the expression evaluated either by exception or periodically, or both. If
you choose both, the expression will be evaluated once every X milliseconds as well as anytime
there is a transition on a data point or signal used in the expression. If you do not choose either
method, the expression will be evaluated only once, on the SMP Gateway’s startup.
Note: This function is not available for the SMP 4-20 and the SMP 8-40.
To create a calculated data point:
In the left pane, at the bottom of the automated functions list, expand Functions and right-
click Logic Processor.
In the shortcut menu, select Logic Editor.
SMP Config displays the Logic Editor dialog box.
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