Communication Through Refresh - Mitsubishi Electric MELSEC iQ-R Series User Manual

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.
Refresh timing
At the END processing
At the execution of multiple CPU
synchronous interrupt program (I45)
*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.
Time
Sequence scan
Program
Multiple CPU
communication 0.888ms
cycle
23 MULTIPLE CPU SYSTEM FUNCTION
352
23.4 Data Communication Between CPU Modules
Application
For data communication of devices in synchronization with the scan
For data communication of devices at the period specified in the fixed scan
*1*2
communication setting
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)
:
1 scan
END
0.888ms 0.888ms
Cycle that is set for the multiple CPU communication cycle setting
1 scan
END
0.888ms
Memory to be used
CPU buffer memory
Fixed scan communication
area