B.2.2 memobus rtu mode, Coil status read – Yaskawa MP920 Communications Module User Manual
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B.2 MEMOBUS Messages
B-19
B
List of MEMOBUS Commands
The commands that make up the MEMOBUS messages are identified by a function code,
and have the functions shown in the following table.
B.2.2
MEMOBUS RTU Mode
Coil Status Read
Function Code
Function
MEMOBUS
(RTU)
MEMOBUS
(ASCII)
01H
Coil status read
2,000 points
976 points
02H
Input relay status read
2,000 points
976 points
03H
Holding register write
125 words
61 words
04H
Input register read
125 words
61 words
05H
Single coil status change
1 point
1 point
06H
Single holding register write
1 word
1 word
08H
Loopback test
−
−
0FH
Multiple coil status change
800 points
800 points
10H
Multiple holding register write
100 words
59 words
The function code is 01H when the coil status is read.
Set the leading address of the coils to be read.
Set the number of coils to read.
Error check
Slave address
Function code: 01H
Start No.
No. of colis
CRC-16
(L)
(H)
(L)
(H)
(L)
(H)
Command
7
0
Slave address
Function code: 01H
No. of data items
Status of first 8 coils
Status of next 8 coils
Status of next 8 coils
CRC-16
(L)
(H)
The function code is 01H when the coil status is read.
The byte length of the read data is returned.
The read data contents are returned.
Error check
Response
7
0