Mitsubishi Electric Q81BD-J61BT11 User Manual page 28

1 OVERVIEW
Personal computer
Program
Read
mdReceive
Write
mdSend
Write
mdSend
Read
mdReceive
Personal computer
Program
Write
mdSend
Read
mdReceive
Write
mdSend
Read
mdReceive
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(3) Local station communication
The communication between the master station and the local station uses two
types of transmission methods: cyclic transmission and transient transmission.
(a) Cyclic transmission
Data communication between stations 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
CC-Link Ver.2 board
Remote input
RX
Remote output
RY
Remote
register
RWw
Remote
register
RWr
(b) Transient transmission
Read and write operations can be performed for the local station buffer
memory and CPU device at an arbitrary timing (using the mdReceive and
mdSend functions, respectively).
Master station
CC-Link Ver.2 board
Transient
transmission
Transient
transmission
Transient
transmission
Transient
transmission
Local station
Remote output
RY
Link scan
Remote input
RX
Link scan
Remote
register
RWr
Link scan
Remote
register
RWw
Link scan
Local station
Buffer memory
MELSEC
PLC CPU
Automatic refresh
Automatic refresh
Automatic refresh
Automatic refresh
PLC CPU
D
Y
X
D
D
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