ASDA-B2 Chapter 8 Communications
Revision May, 2018 8-11
RTU Mode:
Command message (Master): Response message (Slave):
Slave Address 01H Slave Address 01H
Function 06H Function 06H
Starting data
address
02H (High)
Starting data
address
02H (High)
00H (Low) 00H (Low)
Content of data
00H (High)
Content of data
00H (High)
64H (Low) 64H (Low)
CRC Check Low 89H (Low) CRC Check Low 89H (Low)
CRC Check
High
99H (High)
CRC Check
High
99H (High)
Note: Before and after the transmission in RTU mode, 10 ms of silent interval is needed.
Example 3: function code 10H, write multiple words:
The Master issues command to the 1
st
Slave and writes 0BB8H and 0000H to the starting
address 0112H. That is to say, 0112H is written into 0BB8H and 0113H is written into
0000H. The maximum allowable data in one single access is 10. The Slave sends the
response message to the Master after the writing is completed. The calculation of LRC
and CRC will be described in next chapter.
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