Rockwell Automation FactoryTalk View Site Edition Users Guide - Manual (Page 637)

24 • A DDING LOGIC AND CONTROL
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Checking the syntax of an expression
In the Events editor, to verify that the expression you typed uses correct syntax, click
Check Syntax. If the syntax is invalid, an error is shown in the Check Syntax box.
You can check the syntax of an expression at any time while the Events editor is open.
The syntax is also checked automatically, when you click Accept or OK in the editor.
Creating an events component
An event component consists of two parts: an expression and an action.
When a component in the expression changes, the expression is evaluated. If the
expression’s true state changes from false on the previous evaluation, to true on the
current evaluation, the action is triggered.
These are the tasks involved in setting up events for an application:
1. Create the events in the Events editor.
2. Set the maximum update rate for the events component in the Events Setup dialog
box.
3. Save the events component and give it a name. The file extension .eds is added by the
system.
To create an events component
1. In the Events editor, in the Action box, specify the command, macro or symbol that
will run when the event expression evaluates to true.
2. In the Expression box, create an expression that will determine the conditions for
triggering the action. For more information, see Chapter 20, Creating expressions.
3. Click Accept.
4. If the events component is to contain more than one event, click Next to create another
event.
5. Repeat steps 1 through 4 until all events for the particular component are defined.
6. From the Setup menu, select Event Setup.
7. In the Event Setup dialog box, type a description of the component, specify a
maximum update rate, and then click OK.
8. Click Close.
9. Provide a name for the events component, and then click OK.
For details about options in the Events editor and in the Setup dialog box, click Help.