Chapter 6 Modbus RTU protocol
54
answer(slave side)
Slave
address
function
Number
of bytes
Data
(000008-00000
1)
Data
(000010-00000
9)
Error
check(CRC16)
Low
High
11 H
01 H
02 H
CD H
01 H
**H
**H
6.2 Read Input Status (Func 02-02H)
Read the input of the slave device (refer to 1X state) ON/OFF state
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(slave side)
Slave
address
function
Number
of bytes
Data
Data
Data
Error
check(CRC16)
Low
High
1Byte
1Byte
1Byte
1Byte
1Byte
1Byte
1Byte
1Byte
CRC16
The master side reads the output state of the ten coils 10001 (0000H) to 100010 (0009H)
from the slave side (address 17) (ON: 1, OFF: 0).
Inquiry (master side)
Slave
address
function
initial address
Numbers of data
Error
check(CRC16)
High
Low
High
Low
Low
High
11 H
02 H
00 H
00 H
00 H
0A H
** H
** H
If the value of the slave side coil 100008 (0007H) ~100001 (0000H) is
"ON-ON-OFF-OFF-ON-ON-OFF-ON",