Data Communication Between Cpu Modules In The Multiple Cpu System; Used Memory - Mitsubishi Electric MELSEC iQ-R16MTCPU Programming Manual

1.3
Data Communication Between CPU Modules in the
Multiple CPU System
Data transfer is performed between CPU modules in the Multiple CPU system. Data can be written and read between CPUs
through communication by refreshing or by direct access. Data communication methods are shown below.
Refer to the following for details on data communication between CPU modules (data communication via CPU buffer memory/
fixed scan communication area).
MELSEC iQ-R CPU Module User's Manual (Application)
Communication method Application
Data communication via CPU Use to transfer data based on
buffer memory the timing of the respective CPU
modules.
Data communication via fixed Use to transfer data based on
scan communication area the timing between CPU
modules.

Used memory

Data communication between CPU modules uses the CPU buffer memory.
CPU buffer memory configuration
The CPU buffer memory configuration is shown below.
0
to
2047
2048
to
524287
524288
to
999999
1000000
to
2097151
(Fixed scan communication area)
0
to
(Fixed scan communication
area setting points - 1)
Memory Communication method
CPU buffer memory Communication by direct
access
Refresh area Communication by refresh
Fixed scan Communication by direct
*1
communication area access
Refresh area Communication by refresh
*1 To transfer data using the fixed scan communication area, specify fixed scan communication area settings at GX Works3. Refer to the
following for details on fixed scan communication area settings.
MELSEC iQ-R CPU Module User's Manual (Application)
Details
CPU modules transmitting data write to the self CPU buffer memory. CPU modules
receiving data read from the self CPU buffer memory of the CPU module (other CPU)
from which the data was transmitted.
CPU modules transmitting data write to the self CPU fixed scan communication area
(transmission area). CPU modules receiving data read from the self CPU fixed scan
communication area (receipt area) of the CPU module to which the data was transmitted.
CPU buffer memory
System area
User setting area
Occupies the points for refresh(END) only.
Refresh(END) area When refresh(END) is not used, this can be
used as user setting area.
System area
User setting area
CPU buffer memory
User setting area
Occupies the points for refresh(I45 executing) only.
Refresh(I45 executing)
When refresh(I45 executing) is not used, this
area
can be used as user setting area.
Details
Data reading and writing is performed for the self CPU or
other CPU area.
Data communication is performed by refreshing at END
processing.
Data reading and writing is performed for the self CPU fixed
scan communication area, and self CPU and other CPU data
transfer is performed in fixed scan communication cycles.
Refresh is performed in fixed scan communication cycles.

1.3 Data Communication Between CPU Modules in the Multiple CPU System

Area size
PLC CPU: 512k words
Motion CPU: 2M words
Changes can be made within an
overall range of 0 to 24k words. The
transmission area per module can
be set in the 0 to 12k word range.
1 MULTIPLE CPU SYSTEM
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