Mitsubishi Electric MELSEC Q Series Reference Manual page 344

APPENDICES
(5) Correcting the sequence program
(6) Distance between stations using optical fiber cable
(7) The multiplex master function has been changed in the following
(8) The parallel master function cannot be used since it is not
App - 2
There is no need to change sequence programs such as the interlock program
that used link special relays and link special resistors and the remote access
program that used data link commands.
However, the data link instructions (ZNFR/ZNTO instructions) used for accessing
the buffer memory of the intelligent function module of the remote I/O station and
the data link instructions (ZNRD/ZNWR instructions) used for reading/writing of
the remote station word device cannot be used on the MELSECNET/H remote
I/O network. Accordingly, on the MELSECNET/H, rewrite the ZNFR/ZNTO
instructions to REMFR/REMTO instructions and the ZNRD/ZNWR instructions to
READ/WRITE instructions.
• The link special relays and link special register operations used in the
MELSECNET/10 remote I/O network are the same in the MELSECNET/H
network.
When the remote I/O network speed is changed to 25 Mbps, the distance
between stations connected by optical fiber cable will become shorter.
Accordingly, the communication speed can either be set to 10 Mbps or another
optical fiber cable can be installed.
specifications.
Processing when the faulty multiplexed remote master station has returned to
system normally:
• The multiplexed remote master station of the MELSECNET/10 cannot
participate in a data link if it returns to normal while the remote I/O stations are
being controlled by the multiplexed remote sub-master station.
• The multiplexed remote master station of the MELSECNET/H can participate
in a data link as the sub-master/master operating station by making parameter
setting.
supported.
MELSEC-Q
A
App - 2