Goodrive3000 series medium voltage VFD
Moudbus protocol
-198-
one byte.
"CMD" is "03H", indicating that the message is a response of the VFD to the 03H command of the master for reading data.
The CMD information occupies one byte.
"Number of bytes" indicates the number of bytes between a byte (not included) and the CRC byte (not included). The
value "04" indicates that there are four bytes of data between "Number of bytes" and "CRC LSB", that is, "MSB of data in
0004H", "LSB of data in 0004H", "MSB of data in 0005H", and "LSB of data in 0005H".
A piece of data contains two bytes, with the MSB on the left and LSB on the right. From the response, the data in 0004H is
1388H, and that in 0005H is 0000H.
CRC check occupies two bytes, with the LSB on the left, and MSB on the right.
8.4.2 Command code 06H, writing a word
This command is used by the master to write data to the VFD. One command can be used to write only one piece of data.
It is used to modify the parameters and running mode of the VFD.
For example, to write 5000 (1388H) to 0004H of the VFD whose address is 02H, the frame structure is as follows.
RTU master command (from the master to the VFD)
START
T1-T2-T3-T4 (transmission time of 3.5 bytes)
ADDR
02H
CMD
06H
MSB of data writing address
00H
LSB of data writing address
04H
MSB of to-be-written data
13H
LSB of to-be-written data
88H
CRC LSB
C5H
CRC MSB
6EH
END
T1-T2-T3-T4 (transmission time of 3.5 bytes)
RTU slave response (from the VFD to the master)
START
T1-T2-T3-T4 (transmission time of 3.5 bytes)
ADDR
02H
CMD
06H
MSB of data writing address
00H
LSB of data writing address
04H
MSB of to-be-written data
13H
LSB of to-be-written data
88H
CRC LSB
C5H
CRC MSB
6EH
END
T1-T2-T3-T4 (transmission time of 3.5 bytes)
Note:
mainly describe the command formats. For the detailed application, see the examples
in section
8.4.3 Command code 08H, diagnosis
Sub-function code description:
Sub-function code
Description
0000
Returned data based on query information
For example, to query about the circuit detection information about the VFD whose address is 01H, the query and return
strings are the same, and the format is described as follows.
RTU master command
