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21 DEVICES
21.7 CPU Buffer Memory Access Device
Precautions
The following describes the precautions for when the module access device is used.
• If data is written to the refresh-target memory using a program while the refresh function is being used, the CPU module
overwrites the data in the target memory at the execution of the refresh function. Thus, the expected operation may not be
acquired. When the refresh function is used, do not write the data directly to the refresh-target memory but write it to the
refresh-source memory.
*1 When the data is transferred from the CPU module to the module, the target memory is the buffer memory or link device. When the data
is transferred from the module to the CPU module, the target memory is the specified device of the CPU module.
21.7 CPU Buffer Memory Access Device
This device accesses memory used by the built-in function of the CPU module, such as data writing/reading between CPU
modules on the multiple CPU system and Ethernet function ( Page 309 Specification method thorough CPU buffer
memory access device)
Specification method
Specify this device with 'Un\Gn'. (Example: U3E1\G4095, U3E2\HG1024)
Specified item Value to be specified
Un (I/O number of the CPU module) CPU No.1 3E0
CPU No.2 3E1
CPU No.3 3E2
CPU No.4 3E3
G (CPU buffer memory area) CPU buffer memory G
Fixed scan communication area HG
n (CPU buffer memory address) 0 to 268435455 (decimal)
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