User manual

Appendix 4 MODBUS Communication
The contents of the specified number are read out in MODBUS address. The holding
register contents are divided into the high 8-bit and low-order 8-bit, and become the data
in the response message in that order.
Example: Read out the slave 1 running status
Command Message Normal Response Message
AbnomalResponse Message
Slave Address 01
Function Code 03
Starting
No.
Upper 00
Lower 20
Quantity
Upper 00
Lower 01
CRC
Upper 85
Lower C0
Slave Address 01
Function Code 03
No. of Data 02
Data
Upper
00
Lower
C1
CRC
Upper
79
Lower
D4
Slave Address 01
Function Code
83
Error Code 03
CRC
Upper 01
Lower 31
Note： No. of Data is double Command Message Quantity
Write-in to single register [06H]
Single specified data item is written in the specified register, specified data is stored in
the specified register. It is necessary to arrange the written data items in the MODBUS
register address table in the order of the upper 1 byte and the lower 1 byte.
Example: Start slave 1.
Command Message Normal Response Message
AbnomalResponse Message
Slave Address 01
Function Code 06
Starting
No.
Upper 00
Lower 01
Quantity
Upper 00
Lower 01
CRC
Upper 19
Lower CA
Slave Address 01
Function Code
86
Error Code 02
CRC
Upper C3
Lower A1
Slave Address 01
Function Code 06
Starting
No.
Upper 00
Lower 01
Quantity
Upper 00
Lower 01
CRC
Upper 19
Lower CA
Feedback loop Test [08H]
The transmitted message is returned unchanged as a response message. This test is used
for checking the signal communication between master and slave. Test data can use any
value.
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