(2) Saving and restoring a local device file
When some programs use a local device, respective local device file data in the standard RAM or a memory card
(SRAM) are exchanged with the device memory data of the CPU module after execution of each program.
For this reason, the scan time increases by the time spent for data exchange.
Sequence program
Local device
For
program A
For
program B
For
program C
Remark
• There are some instructions for which a local device cannot be specified.
For details, refer to the pages describing devices available for each instruction in the following manual.
MELSEC-Q/L Programming Manual (Common Instruction)
• For the concept of the number of words used for the local devices, refer to Page 341, Section 4.2.
Program A
Program B
Restored
Restored
Saved
Local device
For
program A
For
program B
For
program C
CHAPTER 6 CONVENIENT USAGE OF DEVICES
Program C
Restored
Saved
Local device
For
program A
For
program B
For
program C
6
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