TECO 7300CV - Loop Back Testing [08 H]

7300CV MODBUS COMMUNICATION PROTOCOL
File No. :PC-CV-08
Version : 1.A
Page :
27/34
6.5.3 Loop back testing [08H]
The function code is check communication between MASTER and SLAVE, the Instruction message is
returned as a response message without being change, Any values can be used for test codes or data
ASCII Mode
Instruction Message Response Message (Normal) Response Message (Fault)
3AH STX 3AH STX 3AH STX
30H 30H 30H
31H
SLAVE
Address
31H
SLAVE
Address
31H
SLAVE
Address
30H 30H 38H
38H
Function
Code
38H
Function
Code
38H
Function
Code
30H 30H 32H
30H 30H 30H
Error Code
30H 30H ?
30H
Test Codes
30H
Test Codes
?
LRC CHEC
0DH
41H 41H
0AH
END
35H 35H
33H 33H
37H
DATA
37H
DATA
? ?
?
LRC CHECK
?
LRC CHECK
0DH 0DH
0AH
END
0AH
END
RTU Mode
Instruction Message Response Message (Normal) Response Message (Fault)
SLAVE Address 01 H SLAVE Address 01H SLAVE Address 01H
Function Code 08H Function Code 08H Function Code 88H
High
00H
High
00H Error Code 20H Test
Codes
Low 00H
Test
Codes
Low 00H
High
47H
High
A5H
High
A5H
CRC-16
Low
D8H
DATA
Low
37H
DATA
Low
37H
High
DAH
High
DAH
CRC-16
Low
8DH
CRC-16
Low
8DH