Mitsubishi Electric MELSEC iQ-R-R00CPU User Manual page 313

• When using an area within the fixed scan communication area
Data written to the area within the fixed scan communication area on the host CPU module using the write instruction is sent
to other CPU modules at the period specified in the fixed scan communication setting. Other CPU modules read the received
data using the read instruction. Unlike the refresh, data registered during the instruction execution can be directly read.
Ex.
When data written to the fixed scan communication area on the CPU No.1 using the write instruction is read by CPU No.2
using the read instruction:
CPU No.1
CPU buffer memory
Fixed scan communication area of CPU No.1
Refresh area
Fixed scan communication area of CPU No.2
Refresh area
1 Write using a write instruction
Program
Execution of a write instruction
CPU No.1 (programmable controller CPU)
Device
1
U3E0\HG0
D0
Program
SM400
The data is transferred
at multiple CPU
communication cycle.
2 The send data is
transferred to CPU
No.2.
Fixed scan
communication area
2
Send data
of CPU No.1
Send program
The data is transferred
at multiple CPU
communication cycle.
MOV D0 U3E0\HG0
CPU No.2
CPU buffer memory
Fixed scan communication area of CPU No.1
Refresh area
Fixed scan communication area of CPU No.2
Refresh area
3
Program
Execution of a read instruction
CPU No.2 (programmable controller CPU)
Fixed scan
communication area
U3E0\HG0
Send data
of CPU No.1
Program
SM400
16 MULTIPLE CPU SYSTEM FUNCTION
16.4 Data Communication Between CPU Modules
Read using a read instruction
Device
3
D100
Receive program
MOV U3E0\HG0 D100
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