YASKAWA MP920 User Manual page 139

Message Flow
PS-01 MP920 217IF
CPU-01
Protocol
conversion
Local
station
Standard
MEMOBUS
command
Messages
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.
MELSEC
messages
MELSEC
Remote
station
6-23
6.6 217IF Communications Protocols
Serial
6