Goodrive350 IP55 High-ingress Protection Series VFD
Communication protocol
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"Data quantity" indicates the quantity of data to be read (unit: word).
The value of "Start address" is 0004H, and that of "Data quantity" is 0002H, indicating that data
is to be read from the data addresses of 0004H and 0005H.
CRC check occupies two bytes, with the LSB on the left, and MSB on the right.
RTU slave response (transmitted by the VFD to the master)
START
T1-T2-T3-T4 (transmission time of 3.5 bytes)
ADDR
01H
CMD
03H
Number of bytes
04H
MSB of data in 0004H
13H
LSB of data in 0004H
88H
MSB of data in 0005H
00H
LSB of data in 0005H
00H
LSB of CRC
7EH
MSB of CRC
9DH
END
T1-T2-T3-T4 (transmission time of 3.5 bytes)
The definition of the response information is described as follows:
The value of ADDR is 01H, indicating that the message is transmitted by the VFD whose
address is 01H. The ADDR information occupies one byte.
The value of 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 "LSB of CRC", 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 is two bytes, with the MSB on the left and LSB on the right. From the response,
we can see that 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.
9.4.2 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 operation mode of the
VFD.
For example, to write 5000 (1388H) to 0004H of the VFD whose address is 02H, the structure
of the frame is described in the following table.
RTU master command (transmitted by 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
