Mitsubishi Electric Melsec A Series - Page 118

REPLACEMENT OF MELSECNET (II) AND /B (REMOTE I/O NETWORK)
3 - 6
3
(3) Comparison between MELSECNET/B module (twisted pair) and MELSECNET/H module
(optical loop/coaxial bus)
: Compatible, : Partial change required, × : Incompatible
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Item
Specifications
Compat-
ibility
Precautions for replacement
MELSECNET/B module MELSECNET/H module
Twisted pair
Optical loop
(QJ71LP21-25)
Coaxial bus
(QJ71BR11)
Maximum
number of
link points
per
network
X/Y
Max. 2048 points and max. number of
I/O points of CPU module on master
station
8192 points
B-
16384 points
(Remote master station  remote I/O
station: 8192 points,
remote I/O station  remote master
station: 8192 points)
W
• (MELSECNET mode) 1024 points
• (MELSECNET II composite mode)
4096 points
16384 points
(Remote master station  remote I/O
station: 8192 points,
remote I/O station  remote master
station: 8192 points)
Maximum
number of
link points
per
station
Master
station
• (MELSECNET mode) 1024 bytes
• (MELSECNET II composite mode)
Link parameter first half: 1024 bytes
Remote master station  remote I/O
station
{(LY + LB)  8 + (2 × LW)} 1600 bytes
Remote
I/O
station
512 bytes
Remote I/O station  remote master
station
{(LX + LB)  8 + (2 × LW)} 1600 bytes
Maximum number of
I/O points per station
512 points 4096 points
Communication
speed
125kbps/250kbps/500kbps/1Mbps
25Mbps/10Mbps -
-10Mbps
Number of stations
connected in one
network
32 stations (Master station: 1,
local station + remote I/O station: 31)
65 stations
(Remote master
station: 1, remote I/
O station: 64)
-
Set the PLC to PLC network to
a separate network.
--
33 stations
(Remote master
station: 1, remote I/
O station: 32)
Set the PLC to PLC network to
a separate network.
Applicable cable Shielded twisted pair cable
SI optical cable
H-PCF optical
cable
Broad-band
H-PCF optical
cable
QSI optical cable
-
A new optical cable has to be
installed.
-
3C-2V
5C-2V
A new coaxial cable has to be
installed.
Overall distance
125kbps: 1200m
250kbps: 600m
500kbps: 400m
1Mbps: 200m
30km -
-
3C-2V: 300m
5C-2V: 500m
Either use an A6BR10/
A6BR10-DC type repeater
unit, or configure a separate
network.
Distance between
stations
125kbps: 1200m
250kbps: 600m
500kbps: 400m
1Mbps: 200m
Refer to Section
3.2.2.
-
When 1200m is required, use
GI optical cables for all optical
cables, and use QJ71LP21G
as the module.
-
3C-2V: 300m
5C-2V: 500m
Either use an A6BR10/
A6BR10-DC type repeater
unit, or configure a separate
network.
Maximum number of
networks
-239
New MELSECNET/H
parameter (mandatory)