Yaskawa MP920 Communications Module - Manual (Page 274)

B.2 MEMOBUS Messages
B-25
B
B.2.3 MEMOBUS ASCII Mode
With ASCII communications, RTU communications data is converted to ASCII before
being sent and received.
The following diagram shows an example of RTU to ASCII conversion. As shown in the
example, 8-bit application data is converted to two ASCII characters (7 bits).
With the MEMOBUS format, the code (“:”) showing the start of the data is added in front of
the data, and the code (“CL” or “LF”) showing the end of the data is added after the data.
LRC will be the error check.
3AH ;
30H
32H
30H
33H
02H
03H
00H
6BH
24H
74H
00H
03H
30H
30H
30H
33H
No. of data items
30H
30H
36H
42H
Start No.
LRC 38H
44H
0AH
0DH CR
LF
Message start mark
RTU mode 8-bit data is
converted to ASCII
characters.
ASCII mode error check
Message end mark
Slave address
Function code
Slave address
Function code
Start No.
No. of data items
CRC-16
7 0 7 0