App2
3、Read data Quantity≥1.
(Example) Read the SLAVE station No:01 ,S310+ drive’s frequency command.
ASCII Mode
Instruction Message Response Message (Normal) Response(Fault)
STX 3AH
STX 3AH
STX 3AH
SLAVE
Address
30H
SLAVE
Address
30H
SLAVE
Address
30H
31H
31H
31H
Function
Code
30H
Function
Code
30H
Function
Code
38H
33H
33H
33H
Start
Address
32H
DATA number
30H
Error Code
35H
35H
32H
32H
32H
First
holding
register
31H
LRC CHECK
32H
33H
37H
41H
Quantity
30H
37H
END
0DH
30H
30H
0AH
30H
LRC CHECK
37H
31H
33H
LRC CHECK
42H
END
0DH
33H
0AH
END
0DH
0AH
RTU Mode
Instruction Message Response Message (Normal) Response(Fault)
SLAVE
Address
01H
SLAVE
Address
01H
SLAVE
Address
01H
Function
Code
03H
Function
Code
03H
Function
Code
83H
Start
Address
High
25H
DATA number 02H
Error Code
52H
Low
23H
First
holding
register
High
07H
CRC-16
High C0H
Quantity
High
00H
Low
D0H
Low CDH
Low
01H
CRC-16
High
BBH
CRC-16
High
7EH
Low
E8H
Low
CCH
5.2 LOOP BACK testing [08H]
The function code checks communication between MASTER and SLAVE, the Instruction message
is returned as a response message without being changed, Any values can be used for test codes
or data.