Chapter 6 Communication
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18
Chapter 6 Communication
The instrument is provided with standard RS485 series communication interface, in
accordance with international universal standard MODBUS-RTU communication
protocol, supporting No.03 register reading and holding command.
MODBUS standard format (read and hold command from Register 03)
Command format:
Definition
Address
Function
code
Register
address
Data
number
CRC check
Data
ADDR
0x03
M
N
CRC 16
Bytes
1
1
2
2
2
Return format:
Definition
Address
Function
code
Register
address
Data
number
CRC check
Data
ADDR
0x03
2*N
Data
CRC 16
Bytes
1
1
1
2*N
2
Register address description:
Address
Data
type
Data size Function
code
Description
Access
authority
0x0000
short
2 bytes
0x03
DO value
(unit:mg/L, to be
divided by 100)
Read only
0x0001
short
2 bytes
0x03
Temperature
value (unit:
℃
, to
Read only
