YASKAWA MP920 User Manual page 144

6 217IF Module
6.6.3 OMRON Communications
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 OMRON PLC and performs standard MEMOBUS and
OMRON message conversion processing. There is no need for the OMRON message con-
figuration to be recognized by the user application. The user can easily communicate with
the OMRON PLC by using the MSG-SND and MSG-RCV functions and specifying
OMRON as the communications protocol in the 217IF parameter settings.
Due to OMRON protocol-specific restrictions or OMRON sequencer-specific restrictions in
MEMOBUS to OMRON format conversion, there are stricter restrictions than those in the
MEMOBUS protocol, such as the number of words read from a register. Therefore, carefully
read the manuals relating to the devices connected.
Also be sure to refer to the manual relating to the OMRON communications protocol.
The multi-block transmission protocol stipulated in the OMRON protocol is used. Set the
upper limit for the number of words that can be accessed at the one time by a command to
125 words for reading DM words and 100 words for writing DM words (MEMOBUS proto-
col restriction).
OMRON
messages
OMRON
PLC
Remote
station
6-28
Serial