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CHAPTER 2 APPLICATION OF PROGRAMMING
2
2.1 Memory and Files
2.1.3 Files
(c) Calculation example of memory capacity
The following describes a calculation example of memory capacity when parameters and a program are
written to the program memory.
• Conditions
1) CPU module to be written: Q26UDHCPU
2) Writing file: Table below
*1 For file size, refer to Page 50, Section 2.1.3 (4) (a).
3) Reserved area for online change: 500 steps/2000 bytes
• Memory capacity calculation
The memory capacity is calculated in units of file sizes of the CPU module to be written. The file size unit
of the Q26UDHCPU in this example is 1 step/4 bytes. (
Page 50, Section 2.1.3 (4) (a))
1. Calculation of parameter file size
Since the parameter file size is 464 bytes, 116 steps/464 bytes is occupied on the program memory.
2. Calculation of program size
The program size is found by: Program size + reserved area for online change. Since a program is stored
in units of file sizes (1 step), only the amount equal to the program size is occupied.
3. Result
The calculation results of the memory capacities are as shown below.
File name
File size
*1
PARAM.QPA (parameter file) 464 bytes
MAIN.QPG (sequence program) 525 steps / 2100 bytes
File name File size Memory capacity
PARAM.QPA 464 bytes 116 steps (464 bytes)
MAIN.QPG
Sequence program size 525 steps
1025 steps (4100 bytes)Reserved area for online change 500 steps
Total 1025 steps
Total memory capacity 1141 steps (4564 bytes)
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