Mitsubishi Electric MELSEC-A Series Manual page 118

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