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3 PROGRAM ORGANIZATION UNIT (POU)
3.2 Function Block (FB)
Local latch label area
Capacity of local latch label area of instance = Total capacity of data of latched local labels + Capacity of reserved area
The local label area capacity is assigned by using the engineering tool. For details, refer to the following.
GX Works3 Operating Manual
EN/ENO
An EN (enable input) and ENO (enable output) can be appended to a function block, in the same way as a function, to control
its execution.
Page 13 EN/ENO
An actual argument must be assigned to EN when the instance of the function block to which an EN/ENO is added is called.
Creating programs
The program of a function block can be created by using the engineering tool.
Navigation window "FB/FUN" Right-click "Add New Data"
The created program is stored in the FB/FUN file.
[CPU Parameter] "Program Setting" "FB/FUN File Setting"
Up to 64 programs can be stored in one FB/FUN file.
For details on program creation, refer to the following.
■Type of programs
There are two types of function blocks and the program of each function block type is stored in different ways.
• Macro type function block
• Subroutine type function block
For details, refer to the following.
Page 19 Operation overview
The above cannot be selected for module function blocks, standard functions, and standard function blocks.
■Applicable devices and labels
The following table lists the devices and labels that can be used by function block programs.
: Applicable, : Applicable only by instructions (Not applicable as a label indicating a program step)
Capacity of reserved area The capacity of the area reserved to add non-latched local labels and local
instances when executing the online program change function. (fixed at 48
words)
Breakdown Description
Capacity of latched local labels Total capacity of the data areas used for latched local labels.
Capacity of reserved area The capacity of the area reserved to add latched local labels and local
instances when executing the online program change function. (fixed at 16
words)
Item Reference
How to create function programs GX Works3 Operating Manual
Number of FB/FUN files that can be written to a CPU module User's manual (Startup)
Type of device/label Availability
Label (other than pointer type) Global label
Local label
Label (pointer type) Pointer-type global label
Pointer-type local label
Device Global device
Pointer Global pointer
Breakdown Description
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