22 LABELS
22.3 Classes
373
22
22.3
Classes
The label class indicates from which POU and how a label can be used.
Different classes can be selected depending on the type of POU.
Global label
Class
Description
Applicable POU
Program
block
Function block
Function
VAR_GLOBAL
A common label that can be used in both program blocks and
function blocks
VAR_GLOBAL_CONSTANT
A common constant that can be used in both program blocks
and function blocks
VAR_GLOBAL_RETAIN
A latch type label that can be used in both program blocks and
function blocks
Local label
Class
Description
Applicable POU
Program
block
Function block
Function
VAR
A label that can be used within the range of a declared POU.
This label cannot be used in other POUs.
VAR_CONSTANT
A constant that can be used within the range of a declared
POU.
This label cannot be used in other POUs.
VAR_RETAIN
A latch type label that can be used within the range of a
declared POU. This label cannot be used in other POUs.
VAR_INPUT
A label that inputs a value into a function or function block.
This label receives a value, and the received value cannot be
changed in a POU.
VAR_OUTPUT
A label that outputs a value from a function or function block
VAR_OUTPUT_RETAIN
A latch type label that outputs a value from a function block
VAR_IN_OUT
A local label that receives a value and outputs the value from a
POU. The value can be changed in a POU.
VAR_PUBLIC
A label that can be accessed as the public variable from other
POUs
VAR_PUBLIC_RETAIN
A latch type label that can be accessed as the public variable
from other POUs
Summary of Contents for MELSEC iQ-R-R00CPU
Page 2: ......
Page 151: ...9 MONITOR FUNCTION 9 1 Real Time Monitor Function 149 9 MEMO ...
Page 323: ...18 SEQUENCE SCAN SYNCHRONIZATION SAMPLING FUNCTION 321 18 MEMO ...
Page 330: ...328 20 ROUTING SETTING 20 3 Precautions MEMO ...
Page 423: ...26 BASIC CONCEPT 26 8 State Transition of the Redundant System 421 26 MEMO ...
Page 1014: ...1012 APPX Appendix 15 Added and Enhanced Functions MEMO ...
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