Yaskawa MP920 Communications Module - Manual (Page 139)

6.6 217IF Communications Protocols
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6
„ Message Flow
All standard MEMOBUS messages are exchanged between the MP920 and the 217IF Mod-
ule.
The 217IF communicates with the MELSEC Controller and performs standard MEMOBUS
and MELSEC message conversion processing. There is no need for the MELSEC message
configuration to be recognized by the user application. The user can easily communicate
with the MELSEC Controller by using the MSG-SND and MSG-RCV functions and speci-
fying MELSEC as the transmission protocol in the 217IF parameter settings.
Due to MELSEC protocol-specific restrictions or MELSEC sequencer-specific restrictions
in MEMOBUS to MELSEC format conversion, there are stricter restrictions than in the
MEMOBUS protocol, such as the number of words read from a register. Carefully read the
manuals relating to the devices being connected.
Also be sure to refer to the manual relating to MELSEC protocol type 1 commands.
PS-01 MP920
CPU-01
217IF
Protocol
conversion
Local
station
MELSEC
Remote
station
MELSEC
messages
Serial
Standard
MEMOBUS
command
Messages