Mitsubishi Electric Melsec QJ71LP21 Reference Manual page 70

3 SPECIFICATIONS
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(2) Communication using LX/LY
This function allows 1:1 communication between the I/O master station that
controls LX/LY and other stations (maximum of 63 stations in the optical loop
system and maximum of 31 stations in the coaxial bus system and twisted bus
system).
(a) Available device range
Data communication is performed using the input (X) and output (Y) after
the actual I/O of the host.
For the assignments of the link devices (LX/LY) in the network, the I/O
master station and the valid range for writing data for each station are set
on the common parameter LX/LY setting screens (two screens) of the
control station. The actually available device ranges can also be set for
each station with refresh parameters. Up to two stations in a network may
be set as the I/O master stations.
(b) Data communication
The link input (LX) can send/receive the input information of each station in
the block and the link output (LY) can send/receive the output information of
the I/O master station.
For example, in a network consisting of a control station and three normal
stations, the on/off status can be controlled using the input/output devices
between each station and the I/O master station in each block, as shown
below.
Common
parameter
LX/LY settings
Block 1
I/O master
station 1M 1
P
LY LX
LY LX
LX LY
1N 2 1N 3
S S
Block 1
I/O master station
Control Normal
station station
1M 1 1N
S
P
Normal Normal
station station
1N 4 1N
S S
LY
1N 4 1N 2
S S
2
Block 2
I/O master station
3
Block 2
I/O master
station 1N 3
S
LX
LX LY
1N 4
S
MELSEC-Q
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