Specifications

1 - 2
1.2 Features
The PLC to PLC network of MELSECNET/H is designed to provide higher processing
speeds, more capacities, and more functionality while maintaining the connectivity with
the MELSECNET/10; it is easier to use than ever in combination with GX Developer.
Furthermore, the PLC to PLC network of MELSECNET/H has the following features
that were not available with the conventional MELSECNET (II) and MELSECNET/B
data link systems.
(For the remote I/O network, refer to Chapter 5.)
(1) Achievement of a high-speed communication system
(a) The MELSECNET/H enables high-speed communications with 25Mbps and
10Mbps communication speeds. (25Mbps for only optical loop system)
(b) The link scan time has become even faster through the use of processors
specifically designed for linking.
(c) By subdividing ranges with refresh parameters (divided into 64 per one
module (excluding SB and SW)), the refreshing of the areas not used for the
sequence program can be eliminated and the refresh time can be reduced by
refreshing only those required.
Also, because the bus speed between a QCPU and a network module has
been improved, the refresh time has been reduced.
Refresh range
QCPU
device (B)
Station
No. 1
(Host)
Station
No. 2
Each station's total send range
Fra
g
mentation
High-speed bus
Network module
link device (LB)
Station
No. 3
(d) The optical loop system enables even faster levels of data communication
with multiplex transmission.
(2) Large-scale and flexible system configuration
(a) The link device has a larger capacity: 16384 points for the link relay (LB) and
16384 points for the link register (LW).
(b) The number of link points can now be set up to a maximum of 2000 bytes per
station. Furthermore, by installing multiple network modules with the same
network number, the number of link points that equals the "number of cards
2000 bytes" can be sent.
(c) The commands for transmitting and receiving data with other stations on the
MELSECNET/H network system (SEND, RECV, RECVS, READ, SREAD,
WRITE, SWRITE) enable a maximum of 960 words of data to be transmitted
and received.
(d) A system can be expanded to contain a maximum of 239 networks.