Goodrive30 Series VFD Communication protocol
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executed. The time gap is used to distinguish one message from another so that the two
messages are not regarded as one message.
"ADDR" is "01H", indicating that the command is sent to the VFD whose address is 01H. The
ADDR information occupies one byte.
"CMD" is "03H", indicating that the command is used to read data from the VFD. The CMD
information occupies one byte.
"Start address" indicates that data reading is started from this address. It occupies two bytes,
with the high-order bit on the left and low-order bit on the right.
"Data number" indicates number of data to be read (unit: word). "Start address" is "0004H"
and "Data number" is 0002H, indicating that data is to be read from the data addresses of
0004H and 0005H.
CRC check occupies two bytes, with the low-order bit on the left and high-order bit on the
right.
The definition of the response information is described as follows:
"ADDR" is "01H", indicating that the message is sent from the VFD whose address is 01H.
The ADDR information occupies one byte.
"CMD" is "03H", indicating that the message is a VFD response to the 03H command from 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 CHK low-order bit", that is, "High-order bit of data in 0004H",
"Low-order bit of data in 0004H", "High-order bit of data in 0005H", and "Low-order of data in
0005H".
A piece of data is two bytes, with the high-order bits on the left and low-order bit 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 low-order bit on the left and high-order bit on the
right.
7.3.2 Command word 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 running mode of the VFD.
For example, to write 5000 (1388H) to 0004H of the VFD whose slave address is 02H, the
frame structures are described in the following.
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