Omron SYSDRIVE RV Series User Manual page 316

Loopback Test (Function Code: 08 Hex)
The loopback test returns command messages directly as response messages without changing the contents to
check the communications between the master and slave. You can set user-defined test code and data values.
The following table shows a message example when performing a loopback test with the slave 1 Inverter.
Command Message
Slave address
Function code
Test Code
Data
CRC-16
Writing to Multiple Storage Registers (Function Code: 10 Hex)
Write the specified data to each specified storage register from the specified addresses. The written data must
be in the following order in the command message: Higher place 8 bits, then lower place 8 bits, in storage reg-
ister address order.
The following table shows an example of a message when forward operation has been set at a frequency refer-
ence of 60.0 Hz in the slave 1 Inverter by the PLC.
Command Message
Slave Address
Function Code
Start
Address
(register
number)
Quantity
(10H max.)
Number of attached
data bytes
Lead data
Next data
CRC-16
-108
6
01H Slave address
08H Function code
Higher
00H
place
Test Code
Lower
00H
place
Higher
A5H
place
Data
Lower
37H
place
Higher
DAH
place
CRC-16
Lower
8DH
place
01H Slave Address
10H Function Code
Higher
00H
place
Start
Address
Lower
01H
place
Higher
00H
place
Quantity
Lower
02H
place
04H
CRC-16
Higher
00H
place
Lower
01H
place
Higher
02H
place
Lower
58H
place
Higher
63H
place
Lower
39H
place
Response Message
(Normal Message)
01H
08H
Higher
00H
place
Lower
00H
place
Higher
A5H
place
Lower
37H
place
Higher
DAH
place
Lower
8DH
place
Response Message
(Normal Message)
01H
10H
Higher
00H
place
Lower
01H
place
Higher
00H
place
Lower
02H
place
Higher
10H
place
Lower
08H
place
Response Message
(Error Message)
Slave address 01H
Function code 88H
Error Code 01H
Higher
86H
place
CRC-16
Lower
50H
place
Note The MSB of the function code will be
set to 1 when an error occurs.
Response Message
(Error Message)
Slave Address 01H
Function Code 90H
Error code 02H
Higher
CDH
place
CRC-16
Lower
C1H
place
Note The MSB of the function code will be
set to 1 when an error occurs.