Delta ASD-A3-0121, Руководство пользователя

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ASDA-A3 MODBUS Communication
Revision December, 2017
9-7
9
Example 1: function code 03H, accessing multiple words:
The master issues a command to the first slave and reads two continuous words starting from
the start data address 0200H. In the response message from the slave, the content of the start
data address 0200H is 00B1H, and the content of the second data address is 1F40H. The
maximum allowable data in one single access is 10. The calculation of the LRC and CRC codes
is described below.
ASCII mode:
Command Message (Master):
Response Message (Slave):
Start ‘ : ’ Start ‘ : ’
Slave Address
‘0’
Slave Address
‘0’
‘1’ ‘1’
Function
‘0’
Function
‘0’
‘3’ ‘3’
Start Data Address
‘0’
Data Number
(In byte)
‘0’
‘2’ ‘4'
‘0’
Content of Start Data
Address 0200H
‘0’
‘0’ ‘0’
Data Number
(Word)
‘0’ ‘B’
‘0’ ‘1’
‘0’
Content of Second Data
Address 0201H
‘1’
‘2’ ‘F’
LRC Check
‘F’ ‘4’
‘8’ ‘0’
End 1 (0DH) (CR)
LRC Check
‘E’
End 0 (0AH) (LF) ‘8’
End 1 (0DH) (CR)
End 0 (0AH) (LF)
RTU mode:
Command Message (Master):
Response Message (Slave):
Slave Address 01H Slave Address 01H
Function 03H Function 03H
Start Data Address
02H (High)
Data Number
(In byte)
04H
00H (Low)
Data Number
(In word)
00H
Content of Start Data
Address 0200H
00H (High)
02H B1H (Low)
CRC Check Low C5H (Low)
Content of Second Data
Address 0201H
1FH (High)
CRC Check High B3H (High) 40H (Low)
CRC Check Low A3H (Low)
CRC Check High D4H (High)
Note: A silent interval of 10 ms is required before and after each transmission in RTU mode.