Mitsubishi Electric Melsec A Series - 2.2 Performance Specifications Comparisons; 2.2.1 Module performance comparisons

REPLACEMENT OF MELSECNET (II) AND /B (PLC TO PLC NETWORK)
2 - 3
2
2.2.1 Module performance comparisons
(1) Comparison between MELSECNET (II) module (optical loop) and MELSECNET/H module
(optical loop)
(a) SI optical fiber cable, H-PCF optical fiber cable
: Compatible, : Partial change required, × : Incompatible
2.2 Performance Specifications Comparisons
Item
Specifications
Compat-
ibility
Precautions for replacementMELSECNET ( II ) module MELSECNET/H module
Optical loop Optical loop (QJ71LP21-25)
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
(MELSECNET/10 mode),
(MELSECNET/H mode),
(MELSECNET/H extended mode) 8192
points
B
• (MELSECNET mode) 1024 points
• (MELSECNET II mode),
(MELSECNET II composite mode)
4096 points
• (MELSECNET/10 mode) 8192 points
• (MELSECNET/H mode),
(MELSECNET/H extended mode)
16384 points
W
• (MELSECNET mode) 1024 points
• (MELSECNET II mode),
(MELSECNET II composite mode)
4096 points
• (MELSECNET/10 mode) 8192 points
• (MELSECNET/H mode),
(MELSECNET/H extended mode)
16384 points
Maximum number
of link points per
station
• (MELSECNET mode) 1024 bytes
• (MELSECNET II mode),
(MELSECNET II composite mode)
First half: 1024 bytes
Second half: 1024 bytes
• (MELSECNET/10 mode),
(MELSECNET/H mode)
{(LY+LB)  8+(2 × LW)} 2000 bytes
• (MELSECNET/H extended mode)
{(LY + LB)  8 + (2 × LW)} 35840
bytes
When the number of bytes
exceeds 2000, mount two
modules having the same
network No., or set all modules
on the network in the
MELSECNET/H extended
mode.
Communication
speed
1.25Mbps
25Mbps/10Mbps
Number of stations
connected in one
network
65 stations (master station: 1,
local station + remote I/O station: 64)
64 stations
(control station: 1 normal station: 63)
• Set the remote I/O network
to a separate network.
• For the 65th station,
configure a separate
network.
Applicable cable
SI optical cable
H-PCF optical cable
SI optical cable
H-PCF optical cable
Broad-band H-PCF optical cable
QSI optical cable
When using existing SI cables,
the distance between stations
may be shortened. (Refer to
Section 2.2.2.)
Overall distance 10km 30km
Distance between
stations
Refer to Section 2.2.2.
Refer to Section 2.2.2.
To ensure the same distance
as before replacement, either
change the optical cable, or
install a gateway station
midway along existing cables.
Maximum number
of networks
-
239
New MELSECNET/H
parameter (mandatory)
Communication
method
Half duplex bit serial method
Token ring method
Nothing to be noted though the
communication method differs.
Transmission
method
Duplex loop
Modulation method
(Encoding method)
(Modulation method) CMI method
(Encoding method) NRZI coding
Nothing to be noted though the
modulation method differs.
Transmission
format
HDLC standards (frame format)
Error control
system
CRC(X
16
+X
12
+X
5
+1) and retry by a time over
RAS function
• Loop-back function due to error detection or broken cable
• Diagnostic function for checking local link lines
Number of
occupied I/O points
CPU integrated type: 0 point,
standalone:32 points per slot (I/O
assignment: special 32 points)
32 points per slot
(I/O assignment: intelli. 32 points)
When replacing from a CPU
integrated type, an additional
slot (32 points) is required.