Rockwell-automation FactoryTalk View Site Edition Users Guide Manuel d'utilisateur télécharger pdf (Page 551)

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20 • CREATING EXPRESSIONS

20–5

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20 • Placeholder

Using tag names and tag placeholders in expressions

You can use a tag name as part of an expression, or the tag can stand alone as the entire

expression.

To supply a tag name, type it in the Expressions box, or click Tags to browse for and

select a tag in the Tag Browser. Enclose tag names that contain dashes or start with a

number in brackets {} when you use them in an expression.

Use brackets when using wildcard characters (* or ?) to represent multiple tags in an

expression. You can use wildcards, for example, when using HMI tag alarm functions. For

more information about these built-in functions, see page 20-15.

For more information about working with tags, see Chapter 10, Working with tags.

Specifying the area with a tag name

In a FactoryTalk View SE network distributed application, when referring to a tag in a

different area, you can use an absolute or relative reference to the tag.

For more information, see “About tag references” on page 10-6.

Using tag placeholders to specify tag values

In the Graphics editor, you can use tag placeholders instead of tag names, to specify tag

values in expressions.

A tag placeholder is the cross-hatch character (#) followed by a number from 1 to 500.

At run time, tag placeholders in a display are replaced with the values of tags specified in

the parameter file or parameter list that is loaded with the display.

For more information about tag placeholders, see page 16-35.

Using constants in expressions

To provide a constant value for an expression, use any of the following formats:

 Integer (123)

 Floating point (123.45)

 Scientific notation (1.2345E ²)

This wildcard character Does this

? Matches any single character.

* Matches any number of characters, including the

backslash (\) character.

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Rockwell-automation FactoryTalk View Site Edition Users Guide Manuel d'utilisateur Page 551

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