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CHAPTER 6 COMMUNICATIONS AMONG CPU MODULES
6
6.1 Communications Using the CPU Shared Memory
6.1.2 Communications by auto refresh (using the multiple CPU high speed transmission area)
(b) Memory configuration of the multiple CPU high speed transmission area
The following shows the memory configuration of the multiple CPU high speed transmission area.
For the CPU shared memory configuration, refer to Page 118, Section 6.1.
When the COM instruction is used in the program, auto refresh is performed upon execution of the COM instruction.
However, the scan time increases for the time required for the auto refresh. ( MELSEC-Q/L Programming Manual
(Common Instruction))
(c) Executing auto refresh
Auto refresh is executed when the CPU modules are in RUN, STOP, or PAUSE status. The auto refresh
execution status when an error has occurred in any of the CPU modules differs depending on the error.
( Page 159, Section 6.1.4)
No. Name Description
Size
Setting range Setting unit
1)
Multiple CPU high
speed transmission
area
An area used to communicate data among CPU modules in the Multiple
CPU system.
The area up to 14K word is divided and assigned to CPU modules in the
system.
0 to 14K words 1K word
2)
CPU No.n send
area
n (n=1 to 4)
An area used to store send data of each CPU module.
Data sent to other CPU modules are stored in this area.
Data received from other CPU modules are stored in the area as well.
0 to 14K words 1K word
3) User setting area
An area used to communicate data with other CPU modules by
executing instructions using the cyclic transmission area device
0 to 14K words 2 words
4) Auto refresh area An area to communicate data with other CPU modules by auto refresh 0 to 14K words 2 words
1) Multiple CPU high speed
transmission area
2) CPU No.1 send area
2) CPU No.2 send area
2) CPU No.3 send area
2) CPU No.4 send area
3) User setting area
4) Auto refresh area