Mitsubishi Electric MELSEC-A Series Manual page 17

[About symbols used in figures]
MELSECNET( II ) MELSECNET/H
M m Master station L l Local station M Control station N Normal station
P S
R r Remote I/O station M Remote master station R Remote I/O station
R
 stands for the station No.  stands for the network No., and
 stands for the station No.
A
- 15