B.2.2 Memobus Rtu Mode - YASKAWA MP920 User Manual

Appendix B 218IF Messages

B.2.2 MEMOBUS RTU Mode

Input Relay Status Read
Command
7 0
Slave address
Function code: 02H
(H)
Start No.
(L)
(H)
No. of relays
(L)
(H)
CRC-16
(L)
Response
7 0
Slave address
Function code: 02H
No. of data items
Status of first 8 relays
Status of next 8 relays
Status of next 8 relays
(H)
CRC-16
(L)
Holding Register Read
Command
7 0
Slave address
Function code: 03H
(H)
Start No.
(L)
(H)
No. of registers
(L)
(H)
CRC-16
(L)
Response
7 0
Slave address
Function code: 03H
No. of data items
(H)
Contents of first
holding register
(L)
(H)
Contents of next
holding register
(L)
(H)
Contents of next
holding register
(L)
(H)
CRC-16
(L)
The function code is 02H when the relay status is read.
Set the leading address of the relays to be read.
Set the number of relays to be read.
Error check
The function code is 02H when the relay status is read.
The byte length of the read data is returned.
The read data contents are returned.
Error check
The function code is 03H when the holding register contents
are read.
Set the leading address of the holding registers to be read.
Set the number of holding registers to be read.
Error check
The function code is 03H when the holding register
contents are read.
The byte length of the read data is returned.
The read data contents are returned.
Error check
B-20