App 3-8
4.3 Read the data in the holding register [03H]
Master unit reads the contents of the holding register with the continuous number for the
specified quantity.
Note:1. Limit number of read data，RTU: 37，ASCII:17.
2. Can only Continuous read the address of the same Group
3. Read data Quantity≥1.
(Example) Read the SLAVE station No: 01 ,BDI50 drive’s frequency command.
ASCII Mode
Instruction Message Response Message (Normal) Response (Fault)
SLAVE
SLAVE
SLAVE
Function Code
Function Code
Function Code
Start
Address
DATA Number
Error Code
First
holding
register
LRC CHECK
Quantity
END
LRC CHECK
LRC CHECK
END
END
RTU Mode
Instruction Message Response Message (Normal) Response(Fault)
Start
High
Low
holding
High
CRC-16
High
Quantity
High
00H
Low
D0H
Low
CDH
Low
CRC-16
High
CRC-16
Low
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