Appendix A
A-16 DVP-MC operating manual
Abnormality response
code
Explanation
0x01
Illegal command code: command code in the command message PLC
receives is invalid.
0x02
Illegal device address: the address in the command message PLC receives is
invalid.
0x03
Illegal device value: the data content in the command message PLC receives
is invalid.
0x07
1. Check sum error
1.1 Check if the checksum value is correct
2. Illegal command message
2.1 Command message is too short
2.2 Command message exceed the range
Function code: 03 to read one single or multi word-device register value
Data structure of request message:
Data order Name Byte
Byte0 Modbus ID Single byte
Byte1 Function code Single byte
Byte2 High byte
Byte3
Read the start address of the word devices in
DVP10MC11T
Low byte
Byte4 High byte
Byte5
Read the address number of the word devices in
DVP10MC11T
(Counted by Words)
Low byte
Byte6 Low byte of CRC check sum Low byte
Byte7 High byte of CRC check sum High byte
Data structure of response message:
Data order Name Byte
Byte0 Modbus ID Single byte
Byte1 Function code Single byte
Byte2
Read the address number of the word devices in
DVP10MC11T
(Counted by Bytes)
Single byte
Byte3 High byte
Byte4
The address content of the word devices in
DVP10MC11T
Low byte
… High byte
…
The address content of the word devices in
DVP10MC11T
Low byte
Byte n High byte
Byte n+1
The address content of the word devices in
DVP10MC11T
Low byte
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