Mitsubishi Electric MELSEC iQ-R Series User Manual page 360

• 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 buffer memory
Fixed scan communication area of CPU No.1
Fixed scan communication area of CPU No.2
1 Write using a write instruction
Execution of a write instruction
CPU No.1 (programmable controller CPU)
Device
D0
Program
SM400
23 MULTIPLE CPU SYSTEM FUNCTION
358
23.4 Data Communication Between CPU Modules
CPU No.1
Refresh area
Refresh area
Program
Fixed scan
communication area
1
U3E0\HG0
Send data
of CPU No.1
Send program
MOV D0 U3E0\HG0
The data is transferred
at multiple CPU
communication cycle.
2 The send data is
transferred to CPU
No.2.
CPU No.2 (programmable controller CPU)
communication area
2
of CPU No.1
Program
The data is transferred
at multiple CPU
communication cycle.
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 Read using a read instruction
Program
Execution of a read instruction
Fixed scan
U3E0\HG0
3
Send data
D100
Receive program
SM400
MOV U3E0\HG0 D100
Device