Mitsubishi MELSEC Q Series User Manual page 22

1 OVERVIEW
PLC CPU
Automatic refresh
X
Automatic refresh
Y
Automatic refresh
W
Automatic refresh
W
PLC CPU
RIWT
RIRD
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(3) Local station communication
Communication between the master station and the local station uses two types
of transmission methods: cyclic transmission and transient transmission (see
Section 4.2.3).
(a) Cyclic transmission
Data communication between the PLC CPUs can be performed in N:N
mode using bit data (remote input RX and remote output RY) and word data
(remote registers RWw and RWr).
Master station
Remote
input
(RX)
Remote
output
(RY)
Remote
register
(RWw)
Remote
register
(RWr)
(b) Transient transmission
Read (RIRD) or write (RIWT) operation of the local station buffer memory
and CPU device can be performed at any timing.
Master station
Transient
transmission
area
Local station
Remote
Link scan
output
(RY)
Remote
Link scan
input
(RX)
Remote
Link scan
register
(RWr)
Remote
Link scan
register
(RWw)
Local station
Transient transmission
Transient
transmission
Transient transmission
Transient transmission
Buffer
Transient transmission
memory
Automatic refresh
Automatic refresh
Automatic refresh
Automatic refresh
area
MELSEC-Q
PLC CPU
Y
X
W
W
PLC CPU
W
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