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4.3 Read the data in the holding register [03H]
Master unit reads the contents of the holding register with the continuous number for the
specified quantity.
Note:1. Limit number of read data，RTU: 37，ASCII:17.
2. Can only Continuous read the address of the same Group
3. Read data Quantity≥1.
(Example) Read the SLAVE station No: 01 ,BDI50 drive's frequency command.
Instruction Message
3AH
STX
30H
SLAVE
31H
Address
30H
Function Code
33H
32H
35H
Start
Address
32H
33H
32H
35H
Quantity
30H
31H
?
LRC CHECK
?
0DH
END
0AH
Instruction Message
SLAVE Address
Function Code
High
Start
Low
Address
High
Quantity
Low
High
CRC-16
Low
Response Message (Normal)
3AH
30H
31H
30H
33H
30H
32H
31H
37H
37H
30H
?
?
0DH
0AH
Response Message (Normal)
01H
SLAVE Address
03H
Function Code
25H
DATA Number
First
23H
holding
00H
register
01H
CRC-16
7EH
CCH
ASCII Mode
STX
SLAVE
Address
Function Code
DATA Number
First
holding
register
LRC CHECK
END
RTU Mode
01H
03H
02H
High
07H
Low
D0H
High
BBH
Low
E8H
App 3-8
Response (Fault)
3AH
30H
SLAVE
31H
Address
38H
Function Code
33H
35H
Error Code
32H
?
LRC CHECK
?
0DH
0AH
Response(Fault)
SLAVE Address
Function Code
Error Code
High
CRC-16
Low
STX
END
01H
83H
52H
C0H
CDH
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