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5.4 File Operation by GX Developer and Handling Precautions
5.4.4 File size units
5
MEMORIES AND FILES HANDLED BY CPU MODULE
(b) Memory capacity calculation
The memory capacity is calculated on the basis of the file size unit of the write
target CPU module. (
(1) in this section)
The file size unit of the Q25HCPU in this example is 512 steps/2048 bytes
according to (1) in this section.
1) Calculation of parameter file capacity
Although the parameter file capacity is 564bytes, the file occupies a capacity
of 512 steps/2048 bytes since it is stored on the program memory in file size
unit.
2) Calculation of program capacity
The program capacity is the sequence program ca allocate memory
for online change
In this example, it is 525 steps + 500 steps = 1025 steps. However, the file
occupies a capacity of 1536 steps/6144 bytes since it is stored on the program
memory in file size unit (512-step unit for the Q25HCPU in this example).
Figure 5.45 Capacity occupied by file stored in file size unit (Parameter file)
Figure 5.46 Capacity occupied by file stored in file size unit (Program file)
<On program memory>
Parameter
file
Parameter
file
2048 bytes
564 bytes
(512 steps) are
occupied.
<On program memory>
Sequence
program
Sequence
program
Allocate
memory for
online change
Allocate
memory for
online change
1536 steps
525 steps
500 steps
(6144 bytes) are
occupied.
