74
6
. Detailed settings for communications
6.2 Modbus (continued)
Response frame
• Byte counter
The number of bytes of the read data is put here.
• Data 1 to n
The value of the read data is put here.
• CRC-16
This is a check code calculated from the communication address until the end of the data.
Refer to "An example for CRC-16 calculation" for the calculation. (
Command/Response example
The following is an example of reading voltage 1.
(Communication address: When H’01)
Command
Response
Commu
nication
address
Function
code
Byte
Counter
Data 1
Data 1
Data 2
Data 2
H’03
Upper
Lower
Upper
Lower
1
1
1
4 bytes worth of the number of elements
Data n
Data n
CRC-16
Upper
Lower
2
Commu
nication
address
Function
code
Start reading
address
Number of
elements
CRC-16
01
03
0000
0002
C40B
Commu
nication
address
Function
code
Byte
Coun
ter
Data 1
Data 1
CRC-16
01
03
04
0000
0960
FC4B