Variables; Variable Types - Toshiba LC531 Series Instruction Manual

3.2 Variables

3.2.1

Variable types

A variable is memory (or memory area) that can be referred to from programs.
Variables can be classified into different types depending on the purpose. The
detailed specifications of variables are described below.
(1) Classification of variables based on scope
Variables can be classified into the following two types based on the scope of
reference.
■
Local variable
Local variables are effective only within the program. They can be used
as working memory in the program. In programming a user program,
necessary variables can be assigned.
■
Controller global variable
Controller global variables can be shared within the controller. They can
be used to exchange data among different programs. For controller
global variables, structures and sizes are pre-determined.
Program-1
Controller global variable
Local variable
Program-2
Figure 3-3 Variable scope
Unified Controller nv Series Single-Loop Controller LC531 Instruction Manual
Program-3
Local variable
Local variable
3.2 Variables
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