Rockwell Automation FactoryTalk View Machine Edition Users Guide - Manual (Page 483)

23 • Use expressions
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Use tag names and tag placeholders
A tag name can be included as part of an expression or can stand alone as the entire
expression.
To supply a tag name, do one of the following:
 Type a tag name.
You can type a tag name that does not exist in the tag database. When you click OK,
you are prompted to create the tag. You can create it now, or write down the name and
create it later.
 Click the Tags button and select a tag from the Tag Browser.
Enclose tag names that contain dashes or start with a number in braces { } when you use
them in an expression. This distinguishes the characters in the tag name from the
characters in the expression.
You can use string tags as operands with the plus (+) arithmetic operator and with the
relational operators.
Use tag placeholders instead of tag names
The Graphics editor accepts tag placeholders instead of tag names. Placeholders allow
you to use the same display with different sets of tags.
You can use tag placeholders in:
 The graphic display that opens when the application is first run.
 Graphic displays that are opened using a Goto display button.
 Graphic displays that are opened using a display list selector.
 The graphic display that is opened by a logout button.
 The graphic that is opened when auto logout is used.
 Graphic displays that are opened using the Remote Display Number global
connection.
Use parameter files to specify which tags or folders to substitute for which placeholders.
For global objects, you can specify the tags or folders of tags using global object
parameters. For more information about using parameter files and global object
parameters, see Chapter 25.
The tag placeholder can replace any part of a tag name, including folder names. For
example, you could create a parameter file specifying that the tag placeholder
#1=Folder1. You could assign the folder and a tag name to a graphic object’s connection:
#1\Tag1.