Autonics TM4 Series - Read Holding Registers(Func 03-03 H)

1 Modbus RTU Protocol
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1.3 Read holding registers(Func 03–03H)
Read the Binary data of Holding Registers(4X reference) in Slave device.
(1) Query (Master)
Slave
address
Function
Starting address
No. of points
Error check(CRC16)
High
Low
High
Low
Low
High
1Byte
1Byte
1Byte
1Byte
1Byte
1Byte
1Byte
1Byte
(2) Response (Slave)
Slave
address
Function Byte count
Data Data Data
Error
check(CRC16)
High
Low
High
Low
High
Low
Low
High
1Byte 1Byte 1Byte 1Byte 1Byte 1Byte 1Byte 1Byte 1Byte 1Byte 1Byte
If read the 2 values from Holding Register 400001(0000 H) to 400002(0001 H), in Slave(Address
17) from the Master.
 Query (Master)
Slave
address
Function
Starting address
No. of points
Error check(CRC16)
High
Low
High
Low
Low
High
11 H 03 H 00 H 00 H 00 H 02 H ## H ## H
If the value of 400001(0000 H) on Slave is “555(22B H)” and the value of 400002(0001 H) is
“100(64 H)”.
 Response (Slave)
Slave
address
Function Byte count
Data
Data
Error check(CRC16)
High
Low
High
Low
Low
High
11 H 03 H 04 H 02 H 2B H 00 H 64 H ## H ## H
CRC16
CRC16