The following is an example of upgrading a MELSECNET(
ΙΙ
) system to MELSECNET/H by replacing both local
and remote I/O stations with normal stations.
●
Instructions
(1) Replace the MELSECNET(
ΙΙ
) master station with the MELSECNET/H control station, and the
MELSECNET(
ΙΙ
) local and remote I/O stations with the MELSECNET/H normal stations to maintain a single
network configuration. (This is because the controller network and remote I/O network cannot reside on a
single network.)
(2) Add a simple transfer program between LX/LY (link side device) and X/Y (actual I/O device) for the normal
station replaced from the remote I/O station. With this program, the normal station receives LY sent from
the control station by X and transfers it to actual output address Y; the normal station transfers input X to LY
so that the control station can receive it as X.
• MELSECNET(
ΙΙ
): I/O signal transfer between master station and remote station
- Master station input (X) <- Remote station input (X)
- Master station output (Y) -> Remote station output (Y)
•
MELSECNET/H: I/O signal transfer between control station and normal station
- Control station input (X) <- Normal station output (Y)
- Control station output (Y) -> Normal station input (X)
• Although MELSECNET systems may be a combination of local and remote I/O stations, two
separate networks are necessary when upgrading to Q Series. However, if the existing system
contains only a few remote I/O stations, only one network is needed if remote I/O stations are
replaced with normal (local) stations without changing the cable layout or adding new wiring.
• Even when the remote I/O stations are replaced with the normal stations, it is not required to
modify the control (master) station's network related programs.
Solution and Benefit
Master station
Local station 1
MELSECNET(
ΙΙ
) optical loop
Local station 2
Local station 4
(1) System configuration example
Control station (Station 5)
Normal station 1
MELSECNET/H optical loop
Normal station 2
Normal station 4
Remote station: Station 3
Normal station: Station 3
(replacement of remote I/O station)
Current configuration
New configuration after replacement
A3ACPUP21
I/O module
I/O module
I/O module
I/O module
I/O module
A3ACPUP21
I/O module
I/O module
I/O module
I/O module
I/O module
QJ71LP21-25
Q06UDH
CPU
Q06UDH
CPU
Q06UDH
CPU
Q61P
I/O module
I/O module
I/O module
I/O module
I/O module
Q61P
I/O module
I/O module
QJ71LP21-25
I/O module
I/O module
Q61P
I/O module
I/O module
QJ71LP21-25
I/O module
I/O module
Q06UDH
CPU
Q61P
I/O module
I/O module
QJ71LP21-25
I/O module
I/O module
Q02U CPU
Q61P
I/O module
I/O module
QJ71LP21-25
I/O module
A3ACPUP21
I/O module
I/O module
I/O module
I/O module
I/O module
AJ72P25
I/O module
I/O module
I/O module
I/O module
I/O module
A3USHCPU-S1
I/O module
I/O module
I/O module
I/O module
A1SJ71AP21
Replace
Power supply module
Power supply module
Power supply module
Power supply module
Power supply module
4.3
Replace MELSECNET containing a remote I/O station with MELSECNET/H
93
4.3 Replace MELSECNET containing a remote I/O station with MELSECNET/H
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