YASKAWA E7U Programming Manual page 95

Write In Single Holding Register (06H)
Command Message
Slave address
Function code
Register Upper
Address
Lower
Setting Upper
Data
Lower
Upper
CRC-16
Lower
Loopback Test (08H)
The loopback test returns the command message directly as the response message without changing the contents to check the
communications between the master and slave. Set user-defined test code and data values.
The following table shows a message example when performing a loopback test with the slave 1 Drive.
Command Message
Slave address
Function code
High
Byte
Test Code
Low
Byte
High
Byte
Data
Low
Byte
High
Byte
CRC-16
Low
Byte
Response Message
(During Normal Operation)
01H
Slave address
06H
Function code
00H
Register
01H
Address
00H
Setting
01H
Data
98H
CRC-16
0BH
Fig. 67 Function Code 06H Message Example
Response Message
(During Normal Operation)
01H Slave address
08H Function code
00H
Test Code
00H
A5H
Data
37H
DAH
CRC-16
8DH
Fig. 68 Function Code 08H Message Example
Programming 89
01H
06H
Upper 00H
Lower 01H
Upper 00H
Lower 01H
Upper 98H
Lower 0BH
01H
08H
High
00H
Byte
Low
00H
Byte
CRC-16
High
A5H
Byte
Low
37H
Byte
High
DAH
Byte
Low
8DH
Byte
Response Message
(During Error)
Slave address
Function Code
Error code
Upper
CRC-16
Lower
Response Message
(During Error)
Slave address 01H
Function code 88H
Error Code 01H
High
86H
Byte
Low
50H
Byte
01H
86H
21H
82H
78H