K&R GT600-4T132G User Manual page 231

7.5.3 Data Format
The drive supports reading and writing of word-type parameters only. Reading command is 0x03
and writing command is 0x06. It does not support reading and writing of bytes or bits.
The Modbu-RTU protocol communication data format of the drive is as follows:
Master sending 1
Interval of at
Data frame
least 3.5-byte
time
In theory, host computer can read several consecutive parameters (n can reach up to 12) but the
last parameter it reads must not jump to the next parameter group. Otherwise, an error occurs on
response.
Frame of reading
response from
Idle (frame header)
the slave
Frame of writing
command from Idle (frame header)
the master
> 3.5 byte
Frame of writing
response from
Idle (frame header)
the slave
If the slave detects a communication frame error or reading/writing failure is caused by other
reasons, an error frame will be returned as follows:
Frame of reading
response error from
Idle (frame header)
the slave
Frame of writing
response error from Idle (frame header)
the slave
Slave response 1 A
Interval of at
Data frame
least 3.5-byte
time
> 3.5 byte 1 byte 1 byte
Target Read
station command
address 0x03
> 3.5 byte 1 byte 1 byte
Target
Write
station
command
address
0x06
1 byte 1 byte
Target
Write
station
command
address
0x06
> 3.5 byte 1 byte 1 byte 1 byte
Target
0x83
station
address
Calculate CRC
>3.5Byte 1Byte 1Byte
Target
station 0x86
address
Calculate CRC
7. Interfaces and Communication
Master sending 2
B
1 byte (2n) byte
Number
Function code
of bytes
H --- L
(2n)
Calculate CRC
2 byte 2 byte
Parameter Function
address parameter
H --- L H --- L
Calculate CRC
2 byte 2 byte
Parameter Function
address parameter
H --- L H---- L
Calculate CRC
2 byte
Error CRC and
Idle
type L --- H
1Byte 2Byte
Error CRC and
Idle
type L --- H
Slave response 2
2 byte
CRC and
Idle
L ---- H
2 byte
CRC and
Idle
L --- H
2 byte
CRC and
Idle
L --- H
Error type:
01: Command code error
02: Address error
03: Data error
04: Command cannot be handled
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