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MELSEC-Q
1 OVERVIEW
1.2 Features
The MELSECNET/H is designed to provide higher processing speed, more capacity,
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
MELSECNET/H has the following features that were not available with the conventional
MELSECNET (II) and MELSECNET/B data link systems.
(1) Achievement of a high-speed communication system
(a) The MELSECNET/H enables high-speed communications with 25Mbps
and 10Mbps communication speeds.
Communication speeds vary depending on the network system.
Network system Communication speed
Optical loop 10Mbps or 25Mbps 1
Coaxial bus 10Mbps
Twisted bus 156kbps to 10Mbps
1: QJ71LP21-25 and QJ71LP21S-25 only
(b) The link scan time has become even faster through the use of processors
specifically designed for linking.
(c) Refresh parameter area can be subdivided
By subdividing ranges refresh parameter ranges, 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. (Refer to Section 5.7
"Refresh Parameters.")
The number of refresh parameter settings per module is shown below.
Item
Number of settings
Basic model QCPU
Safety CPU
Q00UJCPU
Q00UCPU
Q01UCPU
High Performance model QCPU
Process CPU
Redundant CPU
Universal model QCPU other than listed in the left column.
Link device transfer 8 16 64
SB/SW transfer 1 for each
Also, because the bus speed between a QCPU and a network module has
been improved, the refresh time has been reduced.
Network module
link device (LB)
Refresh range
QCPU
device (B)
Station
No. 1
(Host)
Station
No. 2
Station
No. 3
Each station's
total send range
Fragmentation
High-speed bus
(d) The optical loop system enables even faster levels of data communication
with multiplex transmission (refer to Multiplex Transmission Function in
section 7.6.)
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