Chapter 8 Functions; Basic Applications Of The Functions; Periodic Communications (Cyclic Transmission) - Mitsubishi Electric MELSEC-Q Series User Manual

CHAPTER 8
8.1

Basic Applications of the Functions

8.1.1

Periodic communications (cyclic transmission)

A master/local module communicates with other stations periodically using RX, RY, RWr, and RWw. For example,
controlling the input and output in the CPU module of a master station controls the input and output in a slave station.
(1) Overview of communications
In CC-Link, communications are performed between the master station and slave stations using RX, RY, RWr,
and RWw. Data in RX, RY, RWr, and RWw of the master/local module are stored in the buffer memory.
For assignment and a flow of input/output data, refer to Page 41, Section 3.6.
CPU
module
Station No.0
Device
RX, RWr
4.
RY, RWw
Range of the
master station
sending data to
the station No.1
1.
Range of the
master station
sending data to
the station No.2
Range of the
master station
sending data to
the station No.3
*1 RWr and RWw are not used for a remote I/O station. Note, however, that buffer memory areas are occupied depending
on the mode of the master/local module. (
FUNCTIONS
Remote device station
Master
Intelligent device station
station
Station No.1
Buffer
memory
RX, RWr
3.
Station
Range of the
station No.1
No.1
sending data
3.
Station
No.2
3.
Station
No.3
RY, RWw
2.
Station
No.1
2.
2.
*1
Remote I/O station
Station No.2
RX, RWr
Range of the
station No.2
sending data
RY, RWw
Station
No.2
Data sent from the master station
Data sent from slave stations
Page 46, Section 3.6.3, Page 55, Section 3.6.6)

CHAPTER 8 FUNCTIONS

CPU
Local station
module
Station No.3
Buffer
Device
memory
RX, RWr
Station
No.1
Station
No.2
Station
No.3
RY, RWw
Station
No.1
Station
No.2
Range of the
station No.3
sending data
Area where data is sent to
other stations
8
125