Delta DVP-15MC Series - Page 915

Appendix A. Modbus Communication
A-11
A_
Byte NO. Name Byte
Byte3
Low byte of CRC check sum
Low byte
Byte4
High byte of CRC check sum
High byte
 Example
Write 16#0100 and 16#0200 to the addresses 16#0000 and 16#0001 in DVP-15MC series
controller respectively via function code 16#10. 16#0000 and 16#0001 are Modbus addresses
of %MW0 and %MW1 in DVP-15MC series controller respectively.
Request message: 01 10 00 00 00 02 04 01 00 02 00 F3 33
Response message: 01 10 00 00 00 02 41 C8
 Function code 16#01 reads multiple output bit register values
 Data structure of a request message:
Byte NO. Name Byte
Byte0
Modbus ID Single byte
Byte1
Function code Single byte
Byte2
The start address of controller’s bit registers to be
read
High byte
Byte3
Low byte
Byte4
The number of controller’s bit registers to be read
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 Read the number of bytes of bit registers.
Single byte
Byte3 Read the state value of the bit register.
Single byte
… Read the state value of the bit register.
Single byte
Byte n Read the state value of the bit register.
Single byte
Byte n+1
Low byte of CRC check sum Low byte
Byte n+2
High byte of CRC check sum High byte
 Data structure of an exception response message:
Byte NO. Name Byte
Byte0
Modbus ID
Single byte
Byte1
16#80+ function code
Single byte
Byte2
Exception response message
Single byte
Byte3
Low byte of CRC check sum
Low byte
Byte4
High byte of CRC check sum
High byte