Mitsubishi Electric MELSEC Q Series User Manual page 155

(1) Communication using auto refresh
(a) Operation of auto refresh
Auto refresh allows communications using the auto refresh area of the CPU shared memory.
By making multiple CPU settings in "PLC parameter", data are automatically written/read between all CPU
modules of the multiple CPU system.
As device memory data of other CPUs are automatically read by the auto refresh function, the host CPU can
use those device data.
The following CPU modules in a multiple CPU system can perform auto refresh using auto refresh area in CPU
shared memory.
Auto refresh is a factor for increasing the scan time in the multiple CPU system.
For calculation formulas for the auto refresh time, refer to Section 5.2.
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