Mitsubishi MELSEC Q Series Structured Programming Manual

3-4
3.3 Labels
3.3.1 Global labels
3.3 Labels
Labels include global labels and local labels.
3.3.1 Global labels
The global labels are labels that can be used in program blocks and function blocks.
In the setting of a global label, a label name, a class, a data type, and a device are associated
with each other.
3.3.2 Local labels
The local labels are labels that can be used only in declared POUs. They are individually defined
per POU.
In the setting of a local label, a label name, a class, and a data type are set.
For the local labels, the user does not need to specify devices. Devices are assigned
automatically at compilation.
3.3.3 Label classes
The label class indicates from which POU and how a label can be used. Different classes can be
selected according to the type of POU.
The following table shows label classes.
Table 3.3.3-1 Label classes
Class Description
Applicable POU
Program
block
Function
Function
block
VAR_GLOBAL
Common label that can be used in program blocks and
function blocks
VAR_GLOBAL_CONSTANT
Common constant that can be used in program blocks
and function blocks
VAR
Label that can be used within the range of declared
POUs
This label cannot be used in other POUs.
VAR_CONSTANT
Constant that can be used within the range of declared
POUs
This constant cannot be used in other POUs.
VAR_RETAIN
Latch type label that can be used within the range of
declared POUs
This label cannot be used in other POUs.
VAR_INPUT
Label that receives a value
This label cannot be changed in a POU.
VAR_OUTPUT Label that outputs a value from a function block
VAR_IN_OUT
Local label that receives a value and outputs the value
from a POU
This label can be changed in a POU.

Mitsubishi MELSEC Q Series Specifications

General

Brand	Mitsubishi
Model	MELSEC Q Series
Category	Controller
Language	English