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Variables Section 1-3
1-3-5 Internal Allocation of Variable Addresses
When an instance is created from a function block definition, the CX-Program-
mer internally allocates addresses to the variables. Addresses are allocated
to all of the variables registered in the function block definition except for vari-
ables that have been assigned actual addresses with the AT S e t ti n g s prop-
erty.
Setting Internal Allocation
Areas for Variables
The user sets the function block instance areas in which addresses are allo-
cated internally by the system. The variables are allocated automatically by
the system to the appropriate instance area set by the user.
Setting Procedure
Select Function Block/SFC Memory - Function Block/SFC Memory Allo-
cation from the PLC Menu. Set the areas in the Function Block/SFC Memory
Allocation Dialog Box.
a
b
15 0
15 0
t
Name Type AT Initial Value
Retained
a BOOL
Name Type AT
b
YES
t
TIMER
2000.00
Name Type Initial Value
c
2000.00
Initial Value
Retained
Retained
AT
BOOL
BOOL
Input 0.00
Instance of function block definition A
Output 2.00
Output 5.00
Note: Variable c is an internal
variable, so it is not displayed.
Usage: Inputs
Properties:
Usage: Outputs
Properties:
Usage: Internals
Properties:
Automatic allocation of
addresses by system
Manual allocation of address to
variable in FB by AT Settings option.
Program
FB instance areas
Size (words)
Non-retained area
Retained area
Starting address
Starting address
Starting address
Starting
address
Timer area
Counter area
CIO, H, W,
D, or E Area
H, D, or E
Area
T Area
C Area
Size (words)
Size (Completion
Flags)
Size (Completion
Flags)
Example
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