Rockwell Automation FactoryTalk View Site Edition Users Guide - Manual (Page 629)

24–1
24
24
•
Pla
ceho
lde
r
Adding logic and control
This chapter describes:
 What logic and control is.
 Creating and using macros.
 Creating and using derived tags.
 Defining and using events.
 Creating and using client keys.
About logic and control
In FactoryTalk View Studio, the Logic and Control folder contains editors for setting up
alternative ways of manipulating tag data and issuing commands at run time.
You can set up:
 Derived tags , to derive values from combined tag data.
 Events , to trigger actions when specified events occur.
 Macros , to issue multiple FactoryTalk View SE commands in sequence.
 Client keys , to assign commands to keyboard keys independent of objects or
displays, so that they are always available at run time.
Creating and using derived tags
A derived tag is a tag whose value is the result of an expression. An expression can be
simply a tag name, or it can be an equation made up of tag names, mathematical and
logical operations, special functions, and If-Then-Else logic.
Derived tag calculations are carried out at the FactoryTalk View SE Server (also called the
HMI server).
A derived tags component is a file that contains the definitions of one or more derived
tags. A derived tags component can be run when an HMI server starts, or it can be run
using the DerivedOn command, after the HMI server has started.
Parts of the Derived Tags editor
Use the Derived Tags editor to create derived tag components for an application.