Mitsubishi MELSEC-A Series Reference Manual page 107

5. SPECIFICATIONS
(3)
Table 5.4 Communication range when the link relay (B) and link register (W) ranges are expanded
Sending
Link parameter
(data write)
setting station
station
M
Master station L1/m
(M) for the
L2/m
second tier
L3/m
L1/m
Master station
1
(L1/m) for the
third-tier-1
2
L2/m
Master station
1
(L2/m) for the
third-tier-2
2
Data communication range with expanded link relays (B) and link registers (W)
(a) Link relays (B) and link registers (W) used by the two-tier link cannot be used for
sending data to the local stations connected to any of the third-tier links.
They can be used to send data to the master stations (L1/m, L2/m, ......, Ln/m)
for the third tiers. This is because these master stations execute communication
with the master station for the second tier as local stations for the second tier.
(b) The devices in the range set by the link parameters for the master station for the
third tier cannot be used for sending data to the master station for the second tier
and the local stations for the two-tier link.
The master station for the third tier can only receive data from the local stations
connected to the host station.
For example, L1/m can only receive data from
The expanded link relay (B) and link register (W) device range that can be used
for communication in the system configuration in Fig 5.8 is shown in Table 5.4.
Device range
M
B/W0 to 7F
B/W80 to FF
B/W100 to 17F
B/W180 to 1FF
B/W200 to 2FF
B/W300 to 37F
B/W380 to 3FF
B/W200 to 27F
B/W280 to 37F
B/W380 to 3FF
POINT
Distinguish between the device range to communicate with the stations in the two-
tier link and the device range to communicate with the stations in the three-tier link
and write a program.
As for L1/m station in Table 5.4, for example, use the device range B/W80 to FF
for communication with the stations (M, L2/m, L3/m) connected to the two-tier link.
Use device range B/W200 to 2FF for communication with the stations ( 1,
connected to the three-tier-1 link.
Receive (data read) range
L1/m L2/m L3/m
1
5 - 29
1 and 2.
Remarks
2 '1 '2
Only the stations connected to the
second tier (M, L1/m, L2/m, L3/m)
can be read. Reading of data from
the local stations ( 1,
'2) in the third-tier link is not
possible.
Only the stations connected to the
third tier - 1 (L1/m,
read. Reading of the other stations
(M, L2/m, L3/m,
possible.
Only the stations connected to the
third tier - 2 (L2/m,
be read. Reading of the other
stations (M, L1/m, L3/m,
not possible.
2, '1,
1, 2) can be
'1, '2) is not
'1, '2) can
1, 2) is
2)