Mitsubishi Electric MELSEC iQ-R-R00CPU, User Manual

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16 MULTIPLE CPU SYSTEM FUNCTION
16.4 Data Communication Between CPU Modules
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16
16.4
Data Communication Between CPU Modules
CPU modules within a multiple CPU system can send and transfer data to each other. The refresh communication and direct
access communication enable data writing or reading between CPU modules. The following table lists the data
communication method.
Memory to be used
CPU buffer memory is utilized for data communication between the CPU modules.
Memory configuration of CPU buffer memory
This section describes the memory configuration of CPU buffer memory.
Communication method Application Description
Data communication with CPU buffer
memory This method is used when data is sent
or received at the timing of each CPU
module. The CPU module for sending the data writes data into the CPU Buffer
memory of the host CPU module. The CPU module for receiving data reads
data from the CPU Buffer memory of the sender CPU module (other CPU
modules).
Data communication with fixed scan
communication area This method is used when data is sent
or received through adjusting the
timing between CPU modules. The CPU module for sending the data writes data into the fixed scan
communication area (send area) of the host CPU module. The CPU module
for receiving data reads data from the fixed scan communication area
(receive area) of the host CPU module of the send source CPU module.
Memory Communication method Description Area size
CPU buffer memory Communication through direct
access This area is used to read/write data to
the areas of the host CPU module or
other CPU modules. 512K words fixed
Refresh area Communication through refresh Data communication is conducted
through refresh at END processing.
Fixed scan communication area Communication through direct
access This area communicates the data to
the fixed scan communication area of
the host CPU module, and is used
when the host CPU module area and
another CPU module area transfer
the data at the fixed scan
communication cycles. It is possible to change within the
range of 0 to 24K words in total. The
send area as per unit can be set
within the range of 0 to 12K words.
(
 Page 300 Setting fixed scan
communication area)
The Refresh Area in the Fixed Scan
Communication Area Communication through refresh The refresh operation is conducted at
the fixed scan communication cycle.
CPU buffer memory
Refresh area
Refresh area
Fixed scan communication area
Send area of CPU No.4
Refresh area
Send area of CPU No.3
Refresh area
Send area of CPU No.2
Refresh area
Send area of CPU No.1