Replacement Precautions - Mitsubishi Electric MELSEC-A Series Manual

3
REPLACEMENT OF MELSECNET (II) AND /B (REMOTE I/O NETWORK)

3.7 Replacement Precautions

The following shows the replacement precautions when replacing MELSECNET (II) with
MELSECNET/H.
(1) Cables
For details on precautions for optical cables and coaxial cables, refer to Section 2.2.2 Cable
performance comparisons.
(2) System configuration
(a) System configuration using local stations and remote I/O stations in MELSECNET mode
and MELSECNET II mode
MELSECNET/H system, which is a composite system comprising local stations and remote stations,
provides high-performance functions by making a separation between local stations and remote
stations. It therefore cannot be configured by a mixture of local stations and remote stations. For this
reason, in a MELSECNET (II) system, when replacing a system, which comprises a mixture of local
stations and remote I/O stations connected to a single master station, with a MELSEC/H system, the
following system configuration is necessary. Normal stations are connected to a single control
station, and remote I/O stations are controlled by an additional remote master station (the control
station in a remote I/O system is defined as the "remote master station"). The following shows a
system configuration example.
MELSECNET (II) (optical)
Optical loop
M
L1
L2
3
- 28
System configuration using local and remote stations (optical)
MELSECNET/H (optical)
Optical loop
Network
1N 1 1M 4/2M
S P
1
R3
1N 2
S
Remarks (proposed measure)
• The control station of network No.1
configures a PLC to PLC network that
controls normal station 1 and normal
Network
2R3
R
2
station 2.
• The other network module becomes the
remote master station, and the remote I/O
network system of No.2 is configured.