Omron SYSDRIVE 3G3RV Series User Manual page 297

Slave Address
Set the Inverter address from 0 to 32. If you set 0, commands from the master will be broadcast (i.e., the
Inverter will not return responses).
Function Code
The function code specifies commands. There are three function codes, as shown below.
Function Code
(Hexadecimal)
03H Read storage register contents
08H Loopback test
10H Write multiple storage registers
Data
Configure consecutive data by combining the storage register address (test code for a loopback address) and
the data the register contains. The data length changes depending on the command details.
Error Check
Errors are detected during communications using CRC-16. The CRC-16 data is the remainder of dividing all
of the message data blocks as a continuous string of data by a specific binary number (1 1000 0000 0000
0101), as shown in the following diagram.
8 bits
Slave address
Function code
Start of communications
data
End of communications
data
Function
When calculating the CRC-16 data, the LSB of the slave ad-
dress is treated as the MSB.
Note 1. Although normally the initial value for the CRC-16 calculation is 0, "-1"
(all 16 bits set to 1) is used here instead.
2. The CRC-16 data is calculated using the LSB of the slave address as
the MSB and the last MSB of the communications data as the LSB.
3. Calculate the CRC-16 data for the response message from the slave
and verify that it is the same as the one in the response message.
Fig 6.59
Communications Functions
Command Message
Min. (Bytes) Max. (Bytes) Min. (Bytes)
8 8
8 8
11 41
Response Message
Max. (Bytes)
7 37
8 8
8 8
81
6-