Delta ASDA-A3 Series User Manual page 612

ASDA-A3
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 0201H is 1F40H.
The maximum allowable data in one single access is 10. The calculation of the LRC and CRC
codes is described as follows.
ASCII mode:
Command Message (Master):
Start
Slave Address
Function
Start Data Address
Data Number
(in words)
LRC Check
End 1
End 0
RTU mode:
Command Message (Master):
Slave Address
Function
Start Data Address
Data Number
(in words)
CRC Check Low
CRC Check High
Note: a silent interval of 10 ms is required before and after each transmission in RTU mode.
':'
'0'
'1'
'0'
'3'
'0'
'2'
'0'
'0'
'0'
'0'
'0'
'2'
'F'
'8'
(0DH) (CR)
(0AH) (LF)
01H
03H
02H (High)
00H (Low)
00H
02H
C5H (Low)
B3H (High)
Response Message (Slave):
Start
Slave Address
Function
Data Number
(in bytes)
Content of Start Data
Address 0200H
nd
Content of the 2 Data
Address 0201H
LRC Check
End 1
End 0
Response Message (Slave):
Slave Address
Function
Data Number
(in bytes)
Content of Start Data
Address 0200H
Content of the 2 nd Data
Address 0201H
CRC Check Low
CRC Check High
MODBUS Communication
':'
'0'
'1'
'0'
'3'
'0'
'4'
'0'
'0'
'B'
'1'
'1'
'F'
'4'
'0'
'E'
'8'
(0DH) (CR)
(0AH) (LF)
01H
03H
04H
00H (High)
B1H (Low)
1FH (High)
40H (Low)
A3H (Low)
D4H (High)
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