Appendix A. Modbus Communication
A-13
A_
Byte NO.
Name
Byte
Byte2
Exception response code
Single byte
Byte3
Low byte of CRC check sum
Low byte
Byte4
High byte of CRC check sum
High byte
Note:
The value of Byte 2 in the response message is determined by the values of Byte 4 and
Byte 5 in the request message. For example, the number of the read bit registers in request
message is A. Dividing A by 8 produces B. If the quotient is an integer, the number of bytes
of bit registers in the response message is B. Otherwise the number of bytes will be B+ 1.
See the example below for details.
Example
Read the state value of %QX2.0~%QX3.4 in DVP-15MC series motion controller via function
code 02. The address of %QX2.0 is 16#A010. Suppose %QX2.0~%QX2.7=1000 0001,
%QX3.0~%QX3.4=1 0001.
Request message: 01 02 A0 10 00 0D 9A 0A
Response message: 01 02 02 81 11 19 E4
Function code 16#05 writes one single bit register value
Data structure of a request message:
Byte NO.
Name
Byte
Byte0
Modbus ID
Single byte
Byte1
Function code
Single byte
Byte2
Modbus address of the bit register
High byte
Byte3
Low byte
Byte4
The value written in the bit register
High byte
Byte5
Low byte
Byte6
Low byte of CRC check sum
Low byte
Byte7
High byte of CRC check sum
High byte
Data structure of a response message:
Byte NO.
Name
Byte
Byte0
Modbus ID
Single byte
Byte1
Function code
Single byte
Byte2
Modbus address of the bit register
High byte
Byte3
Low byte
Byte4
The value written in the bit register
High byte
Byte5
Low byte
Byte6
Low byte of CRC check sum
Low byte
Summary of Contents for DVP-15MC Series
Page 19: ...DVP 15MC Series Motion Controller Operation Manual 1 4 _1 MEMO...
Page 23: ...DVP 15MC Series Operation Manual 2 4 _2 MEMO...
Page 31: ...DVP 15MC Series Motion Controller Operation Manual 3 8 _3 MEMO...
Page 75: ...DVP 15MC Series Motion Controller Operation Manual 6 26 _6 MEMO...
Page 87: ...DVP 15MC Series Motion Controller Operation Manual 7 12 _7 MEMO...
Page 432: ...Chapter 8 Logic Instructions 8 345 8_ MEMO...
Page 470: ...DVP 15MC Series Motion Controller Operation Manual 10 34 10 MEMO...
Page 878: ...DVP 15MC Series Motion Controller Operation Manual 11 408 11 1 MEMO...
Page 920: ...DVP 15MC Series Motion Controller Operation Manual A 16 A MEMO...
Page 941: ...D 1 D Explanation of Homing Modes Table of Contents D 1 Explanation of Homing Modes D 2...
Page 966: ...DVP 15MC Series Motion Controller Operation Manual D 26 D MEMO...