Mitsubishi Electric Melsec A Series - 3.3 Functional Comparisons

REPLACEMENT OF MELSECNET (II) AND /B (REMOTE I/O NETWORK)
3 - 10
3
: Compatible, : Partial change required, × : Incompatible
3.3 Functional Comparisons
Item
Description
Compat-
ibility
Precautions for
replacement
MELSECNET (II) module
MELSECNET/B module
MELSECNET/H module
Cyclic transmission
X/Y are used to perform 1:1
communications between the
master station and local
stations, and the master station
and remote I/O stations.
X/Y are used to perform 1:1
communications between the
remote master station and
remote I/O stations.
Transient transmission
• The RFRP/RTOP instructions
issued from the master
station are used to read/write
the buffer memory of special
function modules at remote I/
O stations.
• Other stations are accessed
from GX Developer
connected to the master
station.
• The master station is
accessed from GX Developer
connected to remote I/O
stations.
• The REMFR/REMTO
instructions issued from the
remote master station are
used to read/write the buffer
memory of intelligent function
modules at remote I/O
stations.
• Other stations are accessed
from GX Works2 or GX
Developer connected to the
remote master station.
• The remote master station is
accessed from GX Works2 or
GX Developer connected to
remote I/O stations.
Correct the RFRP/RTOP
instructions for reading/
writing buffer memory on
intelligent function modules
at remote I/O stations to the
REMFR/REMTO
instructions. (Refer to
Section 3.6.2.)
Automatic return
function
When a disconnected remote I/O station returns to normal
status, it is automatically restored and the data link is resumed.
Loopback function
In the case of an optical loop
system and coaxial loop
system, faulty parts are
disconnected when a fault (e.g.
cable disconnection) occurs,
and normal operation is
continued on operable stations
as a result of the loopback.
In the case of an optical loop
system, faulty parts are
disconnected when a fault (e.g.
cable disconnection) occurs,
and normal operation is
continued on operable stations
as a result of the loopback.
Error detection
Faulty parts are detected by the
data of special relays (M9200 to
9255) and special registers
(D9200 to 9255).
Faulty parts are detected by the
data of link special relays (SB0
to 1FF) and link special
registers (SW0 to 1FF).
Change the devices in the
sequence program. (Refer
to Section 3.6.1.)
Self-diagnosis test
function
Set the following test items by
the mode setting switch:
• Self-loopback test
• Station-to-station test
• Forward loop/reverse loop
test
Set the following test items by
the mode setting switch:
• Self-loopback test
• Internal self-loopback test
• Hardware test
Set the following test items in
the network parameters:
• Forward loop/reverse loop
test
• Set the forward loop/
reverse loop test in the
network parameter
settings.
• Substitute the station-to-
station test with the
forward loop/reverse loop
test.