Mitsubishi QD51 Programming Manual page 94

4 THE EXCHANGE BETWEEN THE PLC AND BUFFER MEMORY
Example 1
Master Station
Local Station #3
Example 3
4 - 4
(c) When the CPU (self station) with the communication module attached is a
MELSEC three-tier master station, data from the self station and master
station of the two-tier loop and all local stations and remote I/O stations
within the three-tier loop can be accessed.
Only the buffer memory of the special function module can be accessed for
remote I/O stations.
Master Station
Local Station #3
Remote Station #2
The setting to determine to which PLC communication is to be made is
performed by specifying the station number within the same loop of self
station. However, when performing access to the self station, the station
number is specified as 255.
Master Station (Station Number 0)
Local Station #1 (Station Number 1)
Local Station #2 (Station Number 2)
Local Station #64 (Station Number 64)
Communication Module
255
Location Station #1
3
1
Remote Station #2
2
Master Station
Local Station #3
Remote Station #2
self
(Local Station #1)
station
Communication Module
(Master
Station)
Example 2
Master Station
Communication Module
Self station
255
0 1
Self
(Local Station #1)
station
Communication Module
255
(Master
Station)
MELSEC-Q
(Local Station #1)
The names in
parentheses are
station names
under a three-tier
system.
(Local Station #2)
Specified to 0
Specified to 1
Always specify
Specified to 2
255 when
becoming
a self station
Specified to 64
0
Local Station #1
Remote Station #2
The numbers within
the is the specified
station number.
(Local Station #1)
2
(Local Station #2)
4 - 4