Chapter 6 Modbus RTU protocol
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The value of 000010(0009H)~000009(0008H) is "OFF-ON".
answer(salve side)
Slave
address
function
Number
of bytes
data
(100008-10000
1)
data
(100010-10000
9)
Error
check(CRC16)
Low
High
11 H
01 H
02 H
CD H
01 H
** H
** H
6.3 Read hold memory (Func 03-03H)
Read binary data from the device holding memory (refer to 4X state)
1. Inquiry (master side)
Slave
address
function
initial address
Numbers of data
Error
check(CRC16)
High
Low
High
Low
Low
High
1Byte
1Byte
1Byte
1Byte
1Byte
1Byte
1Byte
1Byte
CRC16
2.
answer(salve side)
Slave
addre
s-s
Func
t-ion
Numbe
r of
bytes
data
data
data
Error
check(CRC16)
Hig
h
Low
High
Low
High
Low
Low
High
1Byte
1Byt
e
1Byte
1By
te
1Byt
e
1Byt
e
1Byt
e
1Byt
e
1Byt
e
1Byte
1Byte
CRC16
Examples
：
The master side reads the values of the two holding memories 400001 (0000H) to 400002
(0001H) from the slave side (address 17).
Inquiry (master side)
