16 MULTIPLE CPU SYSTEM FUNCTION
16.4 Data Communication Between CPU Modules
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Communication through refresh
The device data for each CPU module is written/read only by the parameter settings. Using refresh areas allows data
communication between all or a part of the CPU modules in the multiple CPU system, thereby enabling devices of other CPU
modules to be used by the host CPU module.
Types of refresh
The following table shows the types of refresh.
*1 The fixed scan communication area is refreshed on the cycle specified in the fixed scan communication setting.
*2 Refresh fails if the multiple CPU synchronous interrupt program (I45) does not exist on the program.
The following figure shows the timing of each refresh.
Refresh timing Application Memory to be used
At the END processing For data communication of devices in synchronization with the scan CPU buffer memory
At the execution of multiple CPU
synchronous interrupt program
(I45)
*1*2
For data communication of devices at the period specified in the fixed scan
communication setting
Fixed scan communication area
END END
:
:
:
:
0.888ms 0.888ms 0.888ms 0.888ms
Refresh with the CPU buffer memory (set)
Refresh with the CPU buffer memory (read)
Refresh with the fixed scan communication area (read)
Refresh with the fixed scan communication area (set)
Sequence scan
Program
Multiple CPU
communication
cycle
Cycle that is set for the multiple CPU communication cycle setting
Time
1 scan1 scan
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