
AT381x User's Guide
94
The function code for reading multiple registers is 0x03.
Table 11-5
Read Multiple Registers
Name
Name
Description
Station address
When there is no RS485 address specified, the
default is 01.
0x03
Function code
Starting address
Register start address, please refer to the Modbus
command set
Number of read
registers
0001~006A
(
106
)
The number of registers read continuously. Please
refer to the Modbus command set to ensure that
these register addresses arevalid, otherwise an error
frame will be returned.
CRC-16
Check code
Figure 11-6
Read Multiple Registers
(
0x03
)
Response Frame
Name
Name
Description
Station address
Returned as it was.
0x03
Or 0x83
Function code
No abnormality: 0x03
Error code: 0x83
Number of bytes
= number of registers x 2
For example: 1 register returns 02
Data
Data Read
CRC-16
Check code
11.5
Writing to Multiple Registers
Figure 11-7
Writing to multiple registers
(
0x10
)
Table 11-6
Writing to multiple registers
Name
Name
Description
Station address
When there is no RS485 address specified, the
default is 01.
0x10
Function code
Starting address
Register start address, please refer to the Modbus